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  • 1.
    Abou Nada, Fahed
    et al.
    Lund University, Department of Physics, Division of Combustion Physics, Box 118, Lund, Swede.
    Lantz, Andreas
    Siemens Industrial Turbomachinery AB, Finspång, Sweden.
    Larfeldt, Jenny
    Siemens Industrial Turbomachinery AB, Finspång, Sweden.
    Markocsan, Nicolaie
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Alden, Marcus
    Lund University, Department of Physics, Division of Combustion Physics, Box 118, Lund, Swede.
    Richter, Mattias
    Lund University, Department of Physics, Division of Combustion Physics, Box 118, Lund, Swede.
    Remote temperature sensing on and beneath atmospheric plasma sprayed thermal barrier coatings using thermographic phosphors2016Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 302, s. 359-367Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Investigations on remote temperature sensing of yttria stabilized zirconia (YSZ) thermal barrier coatings (TBCs) at the surface and at the bond-coat/top-coat interface were carried out. Using Y2O3:Eu thermographic phosphor as an embedded temperature sensing layer, sub-surface temperature probing through 300 mu m of atmospheric plasma sprayed YSZ is demonstrated. The Y2O3:Eu thermographic phosphor displays a temperature sensitivity ranging between 400 degrees C up to a maximum of 900 degrees C when utilizing the luminescence originating from the 611 nm emission band. Dysprosium stabilized zirconia (10 wt.% DySZ), a TBC material, is also investigated and established as a temperature sensor from 400 degrees C up to a temperature of 1000 degrees C using both the intensity decay time and emission intensity ratio methods. In addition, the luminescence of presumed optically inactive YSZ materials was spectroscopically investigated in terms of optical interferences caused by impurities. A validation temperature probing measurement through 300 mu m of YSZ top-coat was successfully performed in a SGT-800 Siemens burner running at six different operating conditions in an atmospheric combustion rig. (C) 2016 Elsevier B.V. All rights reserved.

  • 2.
    Adegoke, Olutayo
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Processability of Laser Powder Bed Fusion of Alloy 247LC: Influence of process parameters on microstructure and defects2020Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis is about laser powder bed fusion (L-PBF) of the nickel-based superalloy: Alloy 247LC. Alloy 247LC is used mainly in gas turbine blades and processing the blades with L-PBF confers performance advantage over the blades manufactured with conventional methods. This is mainly because L-PBF is more suitable, than conventional methods, for manufacturing the complex cooling holes in the blades. The research was motivated by the need for academia and industry to gain knowledge about the processability of the alloy using L-PBF. The knowledge is essential in order to eventually solve the problem of cracking which is a major problem when manufacturing the alloy. In addition, dense parts with low void content should be manufactured and the parts should meet the required performance. Thus, the thesis answered some of the important questions related to process parameter-microstructure-defect relationships.

    The thesis presented an introduction in chapter 1. A literature review was made in chapter 2 to 4. In chapter 2, the topic of additive manufacturing was introduced followed by an overview of laser powder bed fusion. Chapter 3 focused on superalloys. Here, a review was made from the broader perspective of superalloys but was eventually narrowed down to the characteristics of nickelbased superalloys and finally Alloy 247LC. Chapter 4 reviewed the main research on L-PBF of Alloy 247LC. The methodology applied in the thesis was discussed in chapter 5. The thesis applied statistical design of experiments to show the influence of process parameters on the defects and microstructure, so a detail description of the method was warranted. This was given at the beginning of chapter 5 and followed by the description of the L-PBF manufacturing and the characterization methods. The main results and discussions, in chapter 6, included a preliminary investigation on how the process parameters influenced the amount of discontinuity in single track samples. This was followed by the results and discussions on the investigation of voids, cracks and microhardness in cube samples (detail presentation was given in the attached paper B). Finally, the thesis presented results of the microstructure obtainable in L-PBF manufactured Alloy 247LC. The initial results of the microstructure investigation were presented in paper A.

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  • 3.
    Adegoke, Olutayo
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Processability of Laser Powder Bed Fusion of Alloy 247LC-Influence of process parameters on microstructure and defects2021Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis is about laser powder bed fusion (L-PBF) of the nickel-basedsuperalloy Alloy 247LC. Alloy 247LC is mainly used in gas turbine blades and processing the blades with L-PBF may confer performance advantage over the blades manufactured with conventional methods. This is mainly because L-PBFis more suitable, than conventional methods, for manufacturing the complex cooling holes in the blades. The research was motivated by the need for academia and industry to gain knowledge about the processability of the alloy using L-PBF. The knowledge is essential to eventually solve the problem of cracking encountered when processing the alloy. In addition, dense parts with low void content should be processed and the microstructure and properties should meett he required performance. Heat-treatment is usually performed to acquire final properties, so it is also of interest to study this aspect. Thus, the thesis answered some of the important questions related to process parameter-microstructure- property relationships.

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  • 4.
    Adegoke, Olutayo
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Andersson, Joel
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Brodin, Håkan
    Materials Technology Additive Manufacturing Product Development-Industrial Gas Turbines, Siemens Industrial Turbomachinery, Finspång, SE-612 83, Sweden.
    Pederson, Robert
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Influence of laser powder bed fusion process parameters on voids, cracks, and microhardness of nickel-based superalloy alloy 247LC2020Inngår i: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 13, nr 17, artikkel-id 3770Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The manufacturing of parts from nickel-based superalloy Alloy 247LC by laser powder bed fusion (L-PBF) is challenging, primarily owing to the alloy’s susceptibility to cracks. Apart from the cracks, voids created during the L-PBF process should also be minimized to produce dense parts. In this study, samples of Alloy 247LC were manufactured by L-PBF, several of which could be produced with voids and crack density close to zero. A statistical design of experiments was used to evaluate the influence of the process parameters, namely laser power, scanning speed, and hatch distance (inherent to the volumetric energy density) on void formation, crack density, and microhardness of the samples. The window of process parameters, in which minimum voids and/or cracks were present, was predicted. It was shown that the void content increased steeply at a volumetric energy density threshold below 81 J/mm3. The crack density, on the other hand, increased steeply at a volumetric energy density threshold above 163 J/mm3. The microhardness displayed a relatively low value in three samples which displayed the lowest volumetric energy density and highest void content. It was also observed that two samples, which displayed the highest volumetric energy density and crack density, demonstrated a relatively high microhardness; which could be a vital evidence in future investigations to determine the fundamental mechanism of cracking. The laser power was concluded to be the strongest and statistically most significant process parameter that influenced void formation and microhardness. The interaction of laser power and hatch distance was the strongest and most significant factor that influenced the crack density. © 2020 by the authors.

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  • 5.
    Adegoke, Olutayo
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Andersson, Joel
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Brodin, Håkan
    Siemens Industrial Turbomachinery, Finspång, 612 83, Sweden.
    Pederson, Robert
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Review of laser powder bed fusion of gamma-prime-strengthened nickel-based superalloys2020Inngår i: Metals, ISSN 2075-4701, Vol. 10, nr 8, artikkel-id 996Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper reviews state of the art laser powder bed fusion (L-PBF) manufacturing of γ′ nickel-based superalloys. L-PBF resembles welding; therefore, weld-cracking mechanisms, such as solidification, liquation, strain age, and ductility-dip cracking, may occur during L-PBF manufacturing. Spherical pores and lack-of-fusion voids are other defects that may occur in γ′-strengthened nickel-based superalloys manufactured with L-PBF. There is a correlation between defect formation and the process parameters used in the L-PBF process. Prerequisites for solidification cracking include nonequilibrium solidification due to segregating elements, the presence of liquid film between cells, a wide critical temperature range, and the presence of thermal or residual stress. These prerequisites are present in L-PBF processes. The phases found in L-PBF-manufactured γ′-strengthened superalloys closely resemble those of the equivalent cast materials, where γ, γ′, and γ/γ′ eutectic and carbides are typically present in the microstructure. Additionally, the sizes of the γ′ particles are small in as-built L-PBF materials because of the high cooling rate. Furthermore, the creep performance of L-PBF-manufactured materials is inferior to that of cast material because of the presence of defects and the small grain size in the L-PBF materials; however, some vertically built L-PBF materials have demonstrated creep properties that are close to those of cast materials.© 2020 by the authors. Licensee MDPI, Basel, Switzerland.

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  • 6.
    Adegoke, Olutayo
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Andersson, Joel
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Brodin, Håkan
    Siemens Industrial Turbomachinery, 612 83, Finspång (SWE).
    Pederson, Robert
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Harlin, Peter
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Sandvik Additive Manufacturing, Sandviken (SWE).
    Influence of laser powder bed fusion process parameters on the microstructure and cracking susceptibility of nickel-based superalloy Alloy 247LC2022Inngår i: Results in Materials, ISSN 2590-048X, Vol. 13, artikkel-id 100256Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Microstructures of material conditions of nickel-based superalloy Alloy 247LC fabricated using laser powder bed fusion (L-PBF) were investigated. Experiments designed in a prior study revealed the L-PBF process parameters for which the material conditions displayed a reduced susceptibility to cracking. Certain process parameters produced material conditions with an increased susceptibility to cracking. In this study, the material conditions were investigated in detail to reveal their microstructure and to determine the cause of cracking. The reason for the transition between a reduced to an increased susceptibility to cracking was examined. The results revealed solidification cracking occurred at high-angle grain boundaries. Solidification cracking may have been promoted at high-angle grain boundaries because of the undercooling contribution of the grain boundary energy. Furthermore, Si segregation was observed in the cracks. Thus, the presence of Si most likely promoted solidification cracking. It was observed that a high crack density, which occurred in the high energy density material condition, was associated with a large average grain size. The fact that certain combination of process parameters produced microstructures with a low susceptibility to cracking, indicates that reliable Alloy 247LC material may be printed using L-PBF by employing improved process parameters. © 2022

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  • 7.
    Adegoke, Olutayo
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Andersson, Joel
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Ojo, Olanrewaju A.
    University of Manitoba, Winnipeg, Canada.
    Brodin, Håkan
    Siemens Industrial Turbomachinery AB, Finspang, Sweden .
    Pederson, Robert
    GKN Aerospace, Redditch, United Kingdom.
    Laser beam powder bed fusion and post processing of alloy 247LC2019Inngår i: MS and T 2019 - Materials Science and Technology, Materials Science and Technology , 2019, s. 27-34Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Alloy 247LC is sensitive to cracking during laser beam powder bed fusion (PBF-LB) manufacturing. Post processing is thus required to close cracks and achieve desired properties. In this study, samples of Alloy 247LC were manufactured by PBF-LB and subsequently post processed by hot isostatic pressing (HIP), HIP + solution and ageing heat treatments. The microstructure was characterized. Results showed cracks in the as-built condition. Cracks were not detected after HIP. Bright microconstituents were observed in the region between the cells, mainly, because of the partitioning of Hf and Ta into the intercellular region, where they presumably form carbides. What is assumed to be oxides were prominent in the microstructure. Thermodynamic calculations showed rapid formation of ?’ precipitates in the alloy, due to the high total concentration of Al and Ta and this was linked to the high hardness values in the as-built condition. © 2019 MS&T19®

  • 8.
    Adegoke, Olutayo
    et al.
    Siemens Energy, Finspång (SWE).
    Kumara, Chamara
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). FEV Sverige AB, Trollhättan (SWE).
    Thuvander, Matttias
    Department of Physics, Chalmers University of Technology, Gothenburg (SWE).
    Deirmina, Faraz
    Siemens Energy, Finspång (SWE).
    Andersson, Joel
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Brodin, Håkan
    Siemens Energy, Finspång (SWE).
    Harlin, Peter
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Sandvik Additive Manufacturing, Sandviken (SWE).
    Pederson, Robert
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Scanning electron microscopy and atom probe tomography characterization of laser powder bed fusion precipitation strengthening nickel-based superalloy2023Inngår i: Micron, ISSN 0968-4328, E-ISSN 1878-4291, Vol. 171, artikkel-id 103472Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Atom probe tomography (APT) was utilized to supplement scanning electron microscopy (SEM) characterizationof a precipitation strengthening nickel-based superalloy, Alloy 247LC, processed by laser powder bed fusion (LPBF). It was observed that the material in the as-built condition had a relatively high strength. Using both SEMand APT, it was concluded that the high strength was not attributed to the typical precipitation strengtheningeffect of γ’. In the absence of γ’ it could be reasonably inferred that the numerous black dots observed in thecells/grains with SEM were dislocations and as such should be contributing significantly to the strengthening.Thus, the current investigation demonstrated that relatively high strengthening can be attained in L-PBF even inthe absence of precipitated γ’. Even though γ’ was not precipitated, the APT analysis displayed a nanometer scalepartitioning of Cr that could be contributing to the strengthening. After heat-treatment, γ’ was precipitated and itdemonstrated the expected high strengthening behavior. Al, Ta and Ti partitioned to γ’. The strong partitioningof Ta in γ’ is indicative that the element, together with Al and Ti, was contributing to the strain-age crackingoccurring during heat-treatment. Cr, Mo and Co partitioned to the matrix γ phase. Hf, Ta, Ti and W were found inthe carbides corroborating previous reports that they are MC. 

  • 9.
    Adegoke, Olutayo
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Polisetti, Satyanarayana Rao
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Xu, Jinghao
    Linköpings universitet, Linköping.
    Andersson, Joel
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Brodin, Håkan
    Siemens Industrial Turbomachinery, Finspång.
    Pederson, Robert
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Harlin, Peter
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Sandvik Additive Manufacturing, Sandviken.
    Influence of laser powder bed fusion process parameters on the microstructure of solution heat-treated nickel-based superalloy Alloy 247LC2022Inngår i: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 183, artikkel-id 111612Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, Alloy 247LC samples were built with different laser powder bed fusion (L-PBF) process parameters. The samples were then subjected to solution heat treatment at 1260 °C for 2 h. The grain size of all the samples increased significantly after the heat treatment. The relationship between the process parameters and grain size of the samples was investigated by performing a design of experiment analysis. The results indicated that the laser power was the most significant process parameter that influenced the grain height and aspect ratio. The laser power also significantly influenced the grain width. The as-built and as-built + heat-treated samples with high, medium, and low energy densities were characterized using a field emission gun scanning electron microscope equipped with an electron backscatter diffraction detector. The micrographs revealed that the cells present in the as-built samples disappeared after the heat treatment. Isolated cases of twinning were observed in the grains of the as-built + heat-treated samples. The disappearance of cells, increase in the grain size, and appearance of twins suggested that recrystallization occurred in the alloy after the heat treatment. The occurrence of recrystallization was confirmed by analyzing the grain orientation spread of the alloy, which was lower and more predominantly <1° in the as-built + heat-treated conditions than in the as-built conditions. The microhardness of the as-built + heat-treated samples were high which was plausible because γ’ precipitates were observed in the samples. However, the L-PBF process parameters had a very low correlation with the microhardness of the as-built + heat-treated samples.

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  • 10.
    Adli, E.
    et al.
    University of Oslo, Oslo, Norway.
    Gjersdal, H.
    University of Oslo, Oslo, Norway.
    Røhne, O.M.
    University of Oslo, Oslo, Norway.
    Dorholt, O.
    University of Oslo, Oslo, Norway.
    Bang, D.M.
    University of Oslo, Oslo, Norway.
    Thomas, D,
    ESS ERIC, Lund, Sweden.
    Shea, T.
    ESS ERIC, Lund, Sweden.
    Andersson, R.
    ESS ERIC, Lund, Sweden.
    Ibison, M.G.
    University of Liverpool and Cockcroft Institute, Daresbury, UK.
    Welsch, C.P
    University of Liverpool and Cockcroft Institute, Daresbury, UK.
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    The Ess Target Proton Beam Imaging Systemas In-Kind Contribution2017Inngår i: Proceedings of IPAC2017, Copenhagen, Denmark, 2017, s. 3422-3425Konferansepaper (Fagfellevurdert)
  • 11.
    Adli, Erik
    et al.
    University of Oslo, Oslo (NOR).
    Gjersdal, Håvard
    University of Oslo, Oslo (NOR).
    Sjøbæk, Kyrre N.
    University of Oslo, Oslo (NOR).
    Christoforo, Grey
    University of Oslo, Oslo (NOR).
    Fackelman, Eric D.
    University of Oslo, Oslo (NOR).
    Røhne, Ole M.
    University of Oslo, Oslo (NOR).
    Ringnes, Jonas S.
    University of Oslo, Oslo (NOR).
    Solbak, Simen R.
    University of Oslo, Oslo (NOR).
    Lithun, Maren C.
    University of Oslo, Oslo (NOR).
    Thomas, Cyrille
    ESS ERIC, Lund (SWE).
    Levinsen, Yngve
    ESS ERIC, Lund (SWE).
    Rosengren, Kaj
    ESS ERIC, Lund (SWE).
    Shea, Thomas
    ESS ERIC, Lund (SWE).
    Bell, Gerard
    STFC (GBR).
    Ibison, Mark
    University of Liverpool and Cockcroft Institute, Daresbury (GBR).
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Björklund, Stefan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Progress Of The Ess Proton Beam Imaging Systems2022Inngår i: LINAC2022, ACoW Publishing , 2022, s. 395-398Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The ESS Target Proton Beam Imaging Systems has the objective to image the 5 MW ESS proton beam as it entersthe spallation target. The imaging systems has to operate in a harsh radiation environment, leading to a number of challenges : development of radiation hard photon sources, long and aperture-restricted optical paths and fast electronics required to provide rapid information in case of beam anomalies. This paper outlines how main challenges of the imaging systems have been addressed, and the status of deployment as ESS gets closer to beam.

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  • 12.
    Agbauduta, Rex
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Crack density and microhardness of Alloy 247LC manufactured by laser powder bed fusion2021Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Additive manufacturing (AM) enables the manufacturing of complex geometries,with beneficial mechanical properties in components used for aircraft and gas turbines applications. Alloy 247LC produced using laser powder bed fusion (L-PBF)is susceptible to cracking during the production process and must be post-processed using hot isostatic pressing (HIP), in addition to solution heat treatment (ST) and ageing heat treatmentsto heal cracks and attain the desired properties.The purpose of this study is to investigate L-PBF Alloy 247LC in both its as-built and as-built + heat-treated states(HIP and HIP + ST + ageing). Cracks, and microhardness were mainly studied. Sections cut in the built direction and transverse to the built direction were investigated in all the conditions i.e. in as-built and heat-treated states. The grains in the Z-Y direction are columnar and orientated in the build direction, while the grains in the X-Y plane are equiaxed. During the heat-treatments of the samples, substantial grain growth occurred indicating recrystallization. The cracks density appeared to be higher in the X-Y plane compared to the Z-Y plane. Cracks were absent after HIP. The microhardness appearedto be higher in the Z-Y plane compared to the X-Y plane in both low and high indentation load. This indicates anisotropy. In addition, low indentation load produced higher microhardness than a higher indentation load. This was observed in both the X-Y and Z-Y planes. It was also observed in the as-built and heat-treated conditions. HIP conditions had lower microhardness values than both the as-built and HIP + ST + Aged conditions. Microhardness values in the as-built is similar to those of the HIP + ST + Aged conditionswhich suggests that γ' does exist in the as-built state.

  • 13.
    Agic, Adnan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Analysis of entry phase in intermittent machining2018Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Cutting forces and vibrations are essential parameters in the assessment of a cutting process. As the energy consumption in the machining process is directly affected by the magnitude of the cutting forces it is of vital importance to design cutting edges and select process conditions that will maintain high tool performance through reduced energy consumption. The vibrations are often the cause of poor results in terms of accuracy, low reliability due to sudden failures and bad environmental conditions caused by noise. The goal of this work is to find out how the cutting edge and cutting conditions affect the entry conditions of the machining operation. This is done utilizing experimental methods and appropriate theoretical approaches applied to the cutting forces and vibrations. The research was carried out through three main studies beginning with a force build-up analysis of the cutting edge entry into the workpiece in intermittent turning. This was followed by a second study, concentrated on modelling of the entry phase which has been explored through experiments and theory developed in the first study. The third part was focused on the influence of the radial depth of cut upon the entry of cutting edge into the workpiece in a face milling application. The methodology for the identification of unfavourable cutting conditions is also explained herein. Important insights into the force build-up process help addressing the correlation between the cutting geometries and the rise time of the cutting force. The influence of the nose radius for a given cutting tool and workpiece configuration during the initial entry is revealed. The critical angle i.e. the position of the face milling cutter that results in unfavourable entry conditions has been explained emphasizing the importance of the selection of cutting conditions. Finally, the theoretical methods utilized for the evaluation of the role of cutting edge geometry within entry phase dynamics has been explored. This has revealed the trends that are of interest for selection of cutting conditions and cutting edge design.

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  • 14.
    Agic, Adnan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Edge Geometry Effects on Entry Phase by Forces and Vibrations2020Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Intermittent machining is in general strongly related to the large impacts in the entry phase and related vibrations. The influence of the impact forces and vibrations on the cutting process is dependent on workpiece material, structural properties of the tool-workpiece system, cutting edge geometries and cutting parameters. Cutting forces adopt generally a periodic behaviour that gives rise to forced vibrations. In addition, self-induced vibrations may arise because of lowrigidity and insufficient damping in the tool-workpiece system at specific cutting parameters. The ability of the cutting tool to carry the loads during the entry phase and minimize the vibrations is often the key parameter for an effective machining operation.This research work is based on the experiments, analytical studies and modelling. It was carried out through six main studies beginning with a force build-up analysis of the cutting edge entry into the workpiece in intermittent turning. This was followed by a second study, concentrated on modelling of the entry phase which has partly been explored through experiments and theory developed in the first study.

    The third part was focused on the influence of the radial depth of cut upon the entry of the cutting edge into the workpiece in a face milling application. The methodology for the identification of unfavourable radial depth of cut is also addressed herein. Next, effects of the cutting edge on the vibrations in an end milling application were investigated. This study was related to a contouring operation with the maximum chip thickness in the entry phase when machining steel, ISO P material.

    The results of this work provide some general recommendations when milling this type of workpiece material. After that, the focus was set on the dynamic cutting forces in milling. The force developments over a tooth engagement in milling showed to be strongly dependent on the cutting edge geometry. A significant difference between highly positive versus highly negative geometry was found.

    The implication of this phenomena on the stress state in the cutting edge and some practical issues were analysed. Finally, the role of the helix angle on the dynamic response of a workpiece was investigated. The modelling technique using force simulation and computation of the dynamic response by means of modal analysis was presented. Extensive experimental work was conducted to compare the modelling and experimentally obtained results. The modelling results showed a similar trend as the experimental results. The influence of helix angle on the cutting forces and the dynamic response was explained in detail.The research conducted in this work contributes to the deeper understanding of the influence of the cutting edge geometry and the cutting parameters on the force build up process during the entry phase. The presented studies investigate the force magnitudes, force rates and dynamic behaviour of the tools and workpieces when machining at the challenging entry conditions. The methodologies applied are focused on the physical quantities as forces and vibrations rather than the experimental studies that evaluate tool life. The methods and results of the research work are of great interest for the design of the cutting tools and optimization of the cutting processes.

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  • 15.
    Agic, Adnan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Seco Tools, Fagersta, Sweden.
    Eynian, Mahdi
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Hägglund, S.
    Seco Tools, Fagersta, Sweden.
    Ståhl, Jan-Eric
    Lund University, Production and Materials Engineering, Lund, Sweden.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Influence of radial depth of cut on dynamics of face milling application2016Inngår i: The 7th International Swedish Production Symposium, SPS16, Conference Proceedings: 25th – 27th of October 2016, Lund: Swedish Production Academy , 2016, s. 1-9Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The choice of milling cutter geometry and appropriate cutting data for certain milling application is of vital importance for successful machining results. Unfavourable selection of cutting conditions might give rise to high load impacts that cause severe cutting edge damage. The radial depth of cut in combination with milling cutter geometry might under some circumstances give unfavourable entry conditions in terms of cutting forces and vibration amplitudes. This phenomenon originates from the geometrical features that affect the rise time of the cutting edge engagement into work piece at different radial depths of cut. As the radial depth of cut is often an important parameter, particularly when machining difficult to cut materials, it is important to explore the driving mechanism behind vibrations generation. In this study, acceleration of the work piece is measured for different radial depths of cut and cutting edge geometries. The influence of the radial depth of cut on the dynamical behaviour is evaluated in time and frequency domains. The results for different radial depths of cut and cutting geometries are quantified using root mean square value of acceleration. The outcome of this research study can be used both for the better cutting data recommendations and improved tool design.

  • 16.
    Agic, Adnan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Eynian, Mahdi
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Hägglund, S.
    Seco Tools, Fagersta, Sweden.
    Ståhl, J-E
    Lund University ,Production and Materials Engineering, Lund Sweden.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Influence of radial depth of cut on entry conditions and dynamics in face milling application2017Inngår i: Journal of Superhard Materials, ISSN 1063-4576, Vol. 39, nr 4, s. 259-270Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The choice of milling cutter geometry and appropriate cutting data for certain milling application is of vital importance for successful machining results. Unfavorable selection of cutting conditions might give rise to high load impacts that cause severe cutting edge damage. Under some circumstances the radial depth of cut in combination with milling cutter geometry might give unfavorable entry conditions in terms of cutting forces and vibration amplitudes. This phenomenon is originated from the geometrical features that affect the rise time of the cutting edge engagement into workpiece at different radial depths of cut. As the radial depth of cut is often an important parameter, particularly when machining difficult-to-cut materials, it is important to explore the driving mechanism behind vibrations generation. In this study, acceleration of the workpiece is measured for different radial depths of cut and cutting edge geometries. The influence of the radial depth of cut on the dynamical behavior is evaluated in time and frequency domains. The results for different radial depths of cut and cutting geometries are quantified using the root mean square value of acceleration. The outcome of this research study can be used both for the better cutting data recommendations and improved tool design.

  • 17.
    Agic, Adnan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Seco Tools, Fagersta, Sweden.
    Eynian, Mahdi
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Ståhl, J. -E
    Lund University, Production and Materials Engineering, Lund, Sweden.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Experimental analysis of cutting edge effects on vibrations in end milling2019Inngår i: CIRP - Journal of Manufacturing Science and Technology, ISSN 1755-5817, E-ISSN 1878-0016, Vol. 24, s. 66-74Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The ability to minimize vibrations in milling by the selection of cutting edge geometry and appropriate cutting conditions is an important asset in the optimization of the cutting process. This paper presents a measurement method and a signal processing technique to characterize and quantify the magnitude of the vibrations in an end milling application. Developed methods are then used to investigate the effects of various cutting edge geometries on vibrations in end milling. The experiments are carried out with five cutting edge geometries that are frequently used in machining industry for a wide range of milling applications. The results show that a modest protection chamfer combined with a relatively high rake angle has, for the most of cutting conditions, a reducing effect on vibration magnitudes. Furthermore, dynamics of a highly positive versus a highly negative cutting geometry is explored in time domain and its dependency on cutting conditions is presented. The results give concrete indications about the most optimal cutting edge geometry and cutting conditions in terms of dynamic behavior of the tool.

  • 18.
    Agic, Adnan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Seco Tools, Fagersta, Sweden.
    Eynian, Mahdi
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Ståhl, Jan Erik
    Lund University, Production and Materials Engineering, Lund, Sweden.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Dynamic effects on cutting forces with highly positive versus highly negative cutting edge geometries2019Inngår i: International Journal on Interactive Design and Manufacturing, ISSN 1955-2513, E-ISSN 1955-2505, Vol. 13, nr 2, s. 557-565Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Understanding the influence of the cutting edge geometry on the development of cutting forces during the milling process is of high importance in order to predict the mechanical loads on the cutting edge as well as the dynamic behavior on the milling tool. The work conducted in this study involves the force development over the entire engagement of a flute in milling, from peak force during the entry phase until the exit phase. The results show a significant difference in the behavior of the cutting process for a highly positive versus a highly negative cutting edge geometry. The negative edge geometry gives rise to larger force magnitudes and very similar developments of the tangential and radial cutting force. The positive cutting edge geometry produces considerably different developments of the tangential and radial cutting force. In case of positive cutting edge geometry, the radial cutting force increases while the uncut chip thickness decreases directly after the entry phase; reaching the peak value after a certain delay. The radial force fluctuation is significantly higher for the positive cutting edge geometry. The understanding of such behavior is important for modelling of the milling process, the design of the cutting edge and the interactive design of digital applications for the selection of the cutting parameters.

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  • 19.
    Ahmadpour, Ali
    et al.
    Amirkabir University of Technology, Department of Mechanical Engineering, Tehran, Iran.
    Noori Rahim Abadi, Seyyed Mohammad Ali
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Thermal-hydraulic performance evaluation of gas-liquid multiphase flows in a vertical sinusoidal wavy channel in the presence/absence of phase change2019Inngår i: International Journal of Heat and Mass Transfer, ISSN 0017-9310, E-ISSN 1879-2189, Vol. 138, s. 677-689Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Turbulent gas-liquid multiphase flows with and without phase change in a vertical wavy channel are addressed. The multiphase flow field is resolved using the volume of fluid method (VOF), and the flow equations are discretized and numerically solved by the well-known finite volume method. As a multiphase system without mass transfer, air/water flow is considered. It is shown that numerical simulation is well capable of predicting the various multiphase flow regimes ranging from slug to bubbly flows inside wavy channels. Moreover, accurate predictions of overall pressure drop are provided by numerical solutions for various air and water flow rates and the phase shift angle between wavy channel walls. Additionally, condensing flows of refrigerant R134a are simulated inside wavy channels. It is found that for almost all the cases considered in the present study, the convective heat transfer coefficient is higher in wavy channels in respect to straight channels. However, a significant pressure drop penalty is observed especially for high mass fluxes across wavy channels. Therefore, the use of the wavy channels for the enhancement of condensing heat transfer is only advisable for low mass fluxes with the phase shift angle of 180°. © 2019 Elsevier Ltd

  • 20.
    Alchafey, Rani
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap.
    Al-Hallis, Yazan
    Högskolan Väst, Institutionen för ingenjörsvetenskap.
    Weld-Bead Geometry Study of Low Heat Input Welding Processes: WAAM Parts2024Independent thesis Basic level (degree of Bachelor), 15 poäng / 22,5 hpOppgave
    Abstract [en]

    Wire arc additive manufacturing (WAAM) is developing quickly due to its advantages such as high productivity and low cost. Cold metal transfer (CMT) is the most well-known gas metal arc welding process (GMAW) which is widely used in WAAM. CMT is a unique process due to its minimized heat input compared to other welding techniques. However, the lower heat input impacts the geometry of the welding bead in the WAAM part. Similarly, Pulsed Multi Control (PMC) by Fronius provides controlled material deposition and bead geometry management through its advanced pulsing technique, offering a distinct approach within WAAM.

    Institutions like GKN, Volvo Penta, BAE system among others use WAAM in their industryand the final geometry of the WAAM part determines the application of use in the manufacturing sector. Therefore, it is important to study the bead geometry of WAAM parts and to understand how different input parameters and conditions affect their geometry. To encourage wider adoption of the WAAM technique in various industries, it is imperative to conduct essential research into the mechanical characteristics of WAAM materials. In pursuit of this objective, we have conducted an extensive investigation into the correlation between the bead geometry and input parameters within WAAM processes.

    The aim of this work is to examine the relationship between bead geometry and the low heat input WAAM process of CMT, and to compare these findings with those of PMC, another distinct variant within the GMAW spectrum. This process involves a comprehensive analysis of the metallographic samples, wherein penetration depth, bead width, height, and toe angle are measured with the assistance of advanced image software. The study involves a literature review with a focus on critical welding parameters, current, voltage and heat input, with an emphasis on understanding the distinctive influences of CMT and PMC in WAAM. Data measurements are conducted using the program Zeisscore 2.7 and the outcomes arethoroughly analyzed and presented in this report.

    In this study comparing eight WAAM samples, we found that CMT, with its lower heat input, leads to shallower penetration and finer bead geometry. In contrast, PMC offers deeper penetration and wider bead dimensions. This highlights the necessity of choosing the right WAAM process (CMT or PMC) based on specific manufacturing needs, significantly influencing the quality and suitability of the final product.

  • 21.
    Alehojat, Mobin
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap.
    Jafari, Reza
    Tarbiat Modares University, Department of Material Science and Engineering, Tehran, 141 15, Iran (IRN).
    Karimi Neghlani, Paria
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Sadeghi, Esmaeil
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Electron beam-powder bed fusion of Alloy 718: Effect of hot isostatic pressing and thermal spraying on microstructural characteristics and oxidation performance2020Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 404, artikkel-id 126626Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Alloy 718 manufactured via electron beam-powder bed fusion (EB-PBF) was coated with a thermally- sprayed NiCoCrAlY coating for enhanced oxidation protection. A high-velocity air fuel technique was used to deposit the coating. The specimens were then subjected to hot isostatic pressing (HIP). Oxidation of the specimens was undertaken in an ambient air environment at 650 and 800 °C for 168 h. The oxidation performance of EB-PBF-built Alloy 718 was improved after the deposition of the coating, particularly at 800 °C. In this temperature, a thick Cr-rich oxide scale was found on the uncoated Alloy 718 specimen, whereas a thin and stable Al-rich oxide scale was formed on the surface of the coated specimen. HIPing enhanced the oxidation resistance of uncoated Alloy 718; however, the oxidation behavior of coated Alloy 718 was negatively affected by HIPing. © 2020 The Authors

  • 22.
    Alehojat, Seyedmobin
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Effect of HVAF sprayed NiCoCrAlY coating on oxidation performance of E B PBF manufactured Alloy 7182019Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    There is an upsurge of research interest on Alloy 718 additively manufactured (AM) by electron beam powder bed fusion (EB-PBF) technique in aero and land-based gas turbine engines. However, the surface quality hence the oxidation performance of the manufactured components is of great concern. Along with surface roughness resulted from partially melted powder particles, surface defects such as balls, satellites, microcracks as well as up-skin and down-skin surfaces can enhance the vulnerability of the manufactured parts to oxidation. When the surface is unable to withstand the exposed environment adequately, oxidation can be triggered. The surface-induced failures are increasingly becoming more challenging as the AM components often have complex geometries that render them even more difficult to finish. So, the relatively poor surface finish is the barrier to the full exploitation of the AM industry.

    In the present study, a NiCoCrAlY coating deposited by high velocity air-fuel (HVAF) technique on EB-PBF manufactured Alloy 718 was investigated. The oxidation behavior of the parts was investigated in an ambient air environment at 650 and 800 °C for 168 h. The oxidation behavior of the coated samples was analyzed by scanning electron microscopy (SEM) equipped with energy disperse spectroscopy (EDS). The oxidation behavior of the parts was significantly improved after deposition of the thermal spray coating. The oxide scale formed on the surface of the EB-PBF Alloy 718 without the coating was rich in Cr and the oxide scale formed on the surface of the EB-PBF Alloy 718 with NiCoCrAlY coating was rich in Al.

  • 23.
    Algenaid, Wael
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Ganvir, Ashish
    GKN Aerospace Engine Systems, Trollhättan, Sweden.
    Calinas, Rosa Filomena
    Innovnano materials, Coimbra, Portugal.
    Varghese, Johny
    University of Hyderabad, Hyderabad, India.
    Rajulapati, Koteswararao V.
    University of Hyderabad, Hyderabad, India.
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    Influence of microstructure on the erosion behaviour of suspension plasma sprayed thermal barrier coatings2019Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 375, s. 86-99Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Thermal barrier coatings (TBCs) are applied on the surface of hot parts of gas turbine engines to increase the turbine efficiency by providing thermal insulation and to protect the engine parts from the harsh environment. Typical degradation of TBCs can be attributed to bond coat oxidation, thermal stress etc. In addition to this, erosion can also lead to partial or complete removal of the TBCs especially when the engine operates under erosive environment such as flying over desert area, near active volcanic or offshore ocean environment. Suspension Plasma Spraying (SPS) is a promising technique for TBC applications by virtue of its ability to produce a strain-tolerant porous-columnar microstructure that combines the benefits of both electron beam physical vapor deposited (EB-PVD) as well as atmospheric plasma sprayed (APS) coatings. This work investigates the influence of various coating microstructures produced by SPS on their erosion behavior. Six different coatings with varied microstructures produced using different suspensions with distinct characteristics were studied and their erosion resistance was compared. Results showed significant influence of SPS TBCs microstructures on the erosion resistance. Furthermore, the erosion resistance of SPS TBCs showed a close correlation between fracture toughness and the erosion rate, higher fracture toughness favours superior erosion resistance. © 2019 Elsevier B.V.

  • 24.
    Alhaddad, Sami
    Högskolan Väst, Institutionen för ingenjörsvetenskap.
    Investigation on Infrared Welding Parameters of Natural Fibre Reinforced Polypropylene Composite2023Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Using more recyclable material and reducing the weight of vehicles has become one of the most common objectives for car manufacturers in Europe. Among them, Volvo cars, which is one of the leaders in automotive industry when it comes to research of human safety and a sustainable future.

    Fibre reinforced plastics, such as: polypropylene/ long glass fibre (PPLGF) and natural fibre reinforced polypropylene (NFPP) composites play a major role in the search for light weight and recyclability design.

    Strength to weight ratio is considered to be one of the most important factors that gives fibre reinforced plastic composites their unique advantage in many industrial applications.

    However, joining natural fibre reinforced polypropylene composites together with other thermoplastics efficiently is still not fully feasible.

    When NFPP composite is used, joining towards other thermoplastics is possible to obtain using available welding methods which melts NFPP and the opposite material at the interface.

    Infrared welding is well known for being a fast, effective, and a very reliable technology when joining plastic/plastic, especially when the two welded parts are dissimilar thermoplastics. In this research collaboration between Volvo cars and University West in Sweden, infrared welding of NFPP with PP LGF was investigated.

    The aim of this project was to find the best infrared welding parameters that can be used when involving NFPP, and to investigate the weldment region and its strength compared to what can be achieved when welding two PP LGF parts.

    In this research, different natural fibres types were investigated to define the best fibre that can be used when welding NFPP. Infrared welding trials were performed on NFPP and PP LGF samples with different welding setups to find the parameters that give the highest strength. This strength was measured by tensile machines for all welded samples. Differential Scanning Calorimetry (DSC) tests were also performed to determine melting temperature as well as degree of crystallinity for both NFPP and PP LGF.

    The results show that, basically, infrared welding between NFPP and PP LGF proved to be feasible, but that the weldment region has lower strength. They hence provide valuable understanding about NFPP infrared welding development in automotive industry. Additional research can enhance Volvo cars' platform to enable better design for further use of NFPP in coming projects, which lead to further light weighting and lower CO2-emissions from vehicles.

  • 25.
    Ali, Wajid
    Högskolan Väst, Institutionen för ingenjörsvetenskap.
    Next Generation Thermal Barrier Coatings by suspension plasma spraying (NextGen TBC)2022Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Thermal barrier coatings (TBCs) are an important part of gas turbine engines. TBC is used for power generation and aerospace applications. TBCs increase engine efficiency of the gas turbine while reducing fuel consumption, lowering maintenance time, and reducing the toxic emissions (CO2). Due to increased demand of the gas turbines, TBCs needs to be improved by making them highly durable, cheaper in cost and operable at higher temperatures. At higher combustion temperatures, material issues such as corrosion, microstructure degradation, and oxidation become severe. But they can be reduced by insulating engine components from the combustion gases. The objective of the project was to develop the new generation TBCs produced by Suspension plasma spray (SPS) that has better durability and performance at higher temperatures than the current state-of-the-art.

    • SPS process used to spray the topcoat material yttria stabilised zirconia (YSZ).

    • Investigating microstructure of the coating.

    • Various tests performed to better understand the influence of the coating microstructure, including erosion test, and Thermal Cycle Fatigue Test.

    • The Porous vertically cracked microstructure showed superior erosion performance compared to the other columnar microstructures.

    • Hardness and Fracture toughness test needs to be performed to understand about erosion of coating and Thermal lifetime.

  • 26.
    Ancona, Antonio
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för produktionssystem (PS). Physics Department, University of Bari ALDO MORO, Bari (ITA).
    Sikström, Fredrik
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för produktionssystem (PS).
    Christiansson, Anna-Karin
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för produktionssystem (PS).
    Nilsen, Morgan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för produktionssystem (PS).
    Mi, Yongcui
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för produktionssystem (PS).
    Kisielewicz, Agnieszka
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för produktionssystem (PS).
    Monitoring and control of directed energy deposition using a laser beam2023Inngår i: Additive Manufacturing of High-Performance metallic Materials / [ed] Pederson, Robert, Andersson, Joel & Joshi, Shrikant V., Elsevier, 2023, 1., s. 612-638Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    To be a successful competitor among other technologies, metallic laser-directed energy depositionusing a laser beam would benefit from the support of intelligent automation making the processrobust, repeatable, and cost-efficient. This calls for technology leaps towards robust and accuratedetection and estimation of the conditions during processing and control schemes for robustperformance. This chapter discusses how developments in sensor technology and model-basedsignal processing can contribute to advancements in in-process monitoring of directed energydeposition using a laser beam and how developments in model-based feedforward- and feedbackcontrol can support automation. The focus is on how machine vision, optical emission spectroscopy,thermal sensing, and electrical process signals can support monitoring, control and better processunderstanding. These approaches are industrially relevant and have a high potential to support amore sustainable manufacturing. 

  • 27.
    Anderberg, Staffan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Beno, Tomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion. Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Pejryd, Lars
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Energy and Cost Efficiency in CNC Machining from a Process Planning Perspective2011Inngår i: 9th Global Conference on Sustainable Manufacturing: Sustainable Manufacturing –Shaping Global Value Creation / [ed] Günther Seliger, 2011, s. 383-389Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The role of process planning as an enabler for cost efficient and environmentally benign CNC machining is investigated in the paper. Specific energy is used as the principal indicator of energy efficient machining and different methods to calculate and estimate this is exemplified and discussed. The interrelation between process planning decisions and production outcome is sketched and process capability can be considered as one factor of green machining. A correlation between total machining cost and total energy use was shown for an experimental case. However, to generalise conclusions, the importance of having reliable data during process planning to make effective decisions should not be underestimated.

    Fulltekst (pdf)
    Anderberg Beno Pejryd - Energy and cost efficiency in CNC machining from a process planning perspective
  • 28.
    Andersson, Joel
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Fabrication and Weldability Aspects of Ni- and Ni–Fe Based Superalloys: A Review2023Inngår i: Proceedings of the 10th International Symposium on Superalloy 718 and Derivatives / [ed] Eric A. Ott, Joel Andersson, Chantal Sudbrack, Zhongnan Bi, Kevin Bockenstedt, Ian Dempster, Michael Fahrmann, Paul Jablonski, Michael Kirka, Xingbo Liu, Daisuke Nagahama, Tim Smith, Martin Stockinger, Andrew Wessman, Springer Cham , 2023, s. 659-696Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Superalloys are commonly used in structural components of aero-engines. Superalloys in general, Ni- and Ni–Fe-based superalloys, belong to an important group of materials used in aerospace applications. Fabrication and associated weldability aspects of structural components for the hot section of aero-engine gas turbines continue to be of high importance to the manufacturing industry within this discipline. Cracking and specifically hot cracking as well as strain age cracking is a serious concern during the welding and additive manufacturing (AM) of these structural components. The cracking phenomena can occur during welding, AM or subsequent heat treatment of precipitation-hardening superalloys. The cracking behaviour can be influenced by several factors, i.e., chemical composition in terms of hardening elements and impurities, the microstructure of base material, and weld zone, together with corresponding welding, AM and post-treatment process parameters. This paper provides a review of Ni- and Ni–Fe-based superalloys concerning fabrication and weldability aspects within the context of structural components of aero-engines. Also, the paper offers insight and analyses to research publication data of welding and AM of superalloys in the context of annual publication developed over the years as well as specific contributions from countries, affiliations, and specific researchers.

  • 29.
    Andersson, Joel
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Review of Weldability of Precipitation Hardening Ni- and Fe-Ni-Based Superalloys2018Inngår i: Proceedings of the 9th International Symposium on Superalloy 718 & Derivatives: Energy, Aerospace, and Industrial Applications / [ed] Ott, E., Liu, X., Andersson, J., Bi, Z., Bockenstedt, K., Dempster, I., Groh, J., Heck, K., Jablonski, P., Kaplan, M., Nagahama, D. and Sudbrack, C., Springer, 2018, s. 899-916Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Fabrication and welding of structural components for the hot section of aero-engines continues to be of high importance to the manufacturing industry of aero-engines. This paper discusses and reviews the literature on hot cracking and strain age cracking, cracking phenomena that can occur during welding or subsequent heat treatment of precipitation hardened Ni- and Fe-Ni-based superalloys. The influence of chemical composition in terms of i.e. hardening elements and impurities, microstructure of base material and weld zone, together with welding processes and corresponding parameters and heat input are discussed and related to the cracking susceptibility of different nickel based superalloys.

  • 30.
    Andersson, Joel
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Welding metallurgy and weldability of superalloys2020Inngår i: Metals, ISSN 2075-4701, Vol. 10, nr 1, artikkel-id 143Artikkel i tidsskrift (Fagfellevurdert)
    Fulltekst (pdf)
    fulltext
  • 31.
    Andersson, Joel
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Hosseini, Vahid
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Neikter, Magnus
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Pederson, Robert
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Welding of special alloys2023Inngår i: Welding of Metallic Materials: Methods, Metallurgy, and Performance / [ed] Fuad Khoshnaw, Elsevier , 2023, s. 279-316Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

    Specialty alloys are a broad group of materials providing superior properties to common materials and are therefore used for more demanding applications. Specialty alloys require sophisticated manufacturing routes, e.g., vacuum metallurgy, to account for all the alloying elements needed to finalize the specific alloy for its intended purpose. The alloys of Duplex stainless steels, superalloys, and Titanium alloys are examples of so-called specialty alloys where aerospace, chemical, and petrochemical industries are just a few areas mentioned where these specialty alloys are frequently used. Duplex stainless steel, had superior mechanical properties and corrosion resistance, making them a sustainable choice for a wide variety of applications i.e., petrochemical industries. The superalloys, and especially the precipitation hardening ones belong to a unique plethora of alloys commonly used in aerospace as well as land-based gas turbines which possess superb mechanical performance at elevated temperatures. However, the superalloys are unfortunately very challenging to process, not at least regarding weld cracking. With their high specific strength and corrosion resistance, titanium alloys are favorable for numerous applications. However, they react readily with oxygen at elevated temperatures and therefore inert atmosphere must be used during welding. 

  • 32.
    Andersson, Joel
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser.
    Jacobsson, J.
    Brederholm, A.
    Hänninen, H.
    Improved understanding of Varestraint Testing: Nickel-based superalloys2016Inngår i: Cracking Phenomena in Welds IV / [ed] Boellinghaus, T., Lippold, J. C. and Cross, C. E., Springer Publishing Company, 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Information about the book:

    This is the fourth volume in the well-established series of compendiums devoted to the subject of weld hot cracking. It contains the papers presented at the 4th International Cracking Workshop held in Berlin in April 2014. In the context of this workshop, the term “cracking” refers to hot cracking in the classical and previous sense, but also to cold cracking, stress-corrosion cracking and elevated temp. solid-state cracking.  A variety of different cracking subjects are discussed, including test standards, crack prediction, weldability determination, crack mitigation, stress states, numerical modelling, and cracking mechanisms.  Likewise, many different alloys were investigated such as aluminum alloys, copper-aluminum dissimilar metal, austenitic stainless steel, nickel base alloys, duplex stainless steel, creep resistant steel, and high strength steel.

  • 33.
    Andersson, Joel
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser.
    Jacobsson, J.
    Lundin, C.
    A Historical perspective on Varestraint testing and the importance of testing parameters2016Inngår i: Cracking Phenomena in Welds IV / [ed] Boellinghaus, T., Lippold, J. C. and Cross, C. E., Springer Publishing Company, 2016Konferansepaper (Fagfellevurdert)
  • 34.
    Andersson, Joel
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Joshi, Shrikant V.Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).Malmsköld, LennartHögskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för produktionssystem (PS).Hanning, FabianHögskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Sustainable Production through Advanced Manufacturing, Intelligent Automation and Work Integrated Learning: Proceedings of the 11th Swedish Production Symposium (SPS2024)2024Konferanseproceedings (Fagfellevurdert)
    Abstract [en]

    Collaboration between those working in product development and production is essential for successful product realization. The Swedish Production Academy (SPA) was founded in 2006 with the aim of driving and developing production research and higher education in Sweden, and increasing national cooperation in research and education within the area of production.

    This book presents the proceedings of SPS2024, the 11th Swedish Production Symposium, held from 23 to 26 April 2024 in Trollhättan, Sweden. The conference provided a platform for SPA members, as well as for professionals from industry and academia interested in production research and education from around the world, to share insights and ideas. The title and overarching theme of SPS2024 was Sustainable Production through Advanced Manufacturing, Intelligent Automation and Work Integrated Learning, and the conference emphasized stakeholder value, the societal role of industry, worker wellbeing, and environmental sustainability, in alignment with the European Commission's vision for the future of manufacturing. The 59 papers included here were accepted for publication and presentation at the symposium after a thorough review process. They are divided into 6 sections reflecting the thematic areas of the conference, which were: sustainable manufacturing, smart production and automation, digitalization for efficient product realization, circular production, industrial transformation for sustainability, and the integration of education and research.

    Highlighting the latest developments and advances in automation and sustainable production, the book will be of interest to all those working in the field.

    Fulltekst (pdf)
    Bokens fulltext
  • 35.
    Andersson, Joel
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser. Department of Materials Technology, Volvo Aero Corporation, Trollha¨ttan, Sweden and Chalmers University of Technology, Gothenburg, Sweden.
    Sjöberg, G.
    Department of Materials Technology, Volvo Aero Corporation, Trollha¨ttan, Sweden and Chalmers University of Technology, Gothenburg, Sweden.
    Repair welding of wrought superalloys: Alloy 718, Allvac 718Plus and Waspaloy2012Inngår i: Science and Technology of Welding and Joining, ISSN 1362-1718, Vol. 17, nr 1, s. 49-59Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The ability to weld repair three precipitation hardening superalloys, i.e. Alloy 718, Allvac 718Plus and Waspaloy, with gas tungsten arc welding, is compared in this study. Four different solution heat treatment conditions for each material were examined: Alloy 718 and Allvac 718Plus heat treated at 954uC–1 h, 982uC–1 h, 954uC–15 h and 1020uC–1 h and Waspaloy for 4 h at 996uC, 1010uC, 1040uC and at 1080uC. By metallography, the total number of cracks was evaluated in both the heat affected zone and the fusion zone, which made it possible to consistently rate the repair weldability of these three materials. Alloy 718 was significantly the best one, with Allvac 718Plus slightly better than Waspaloy. As expected, the solution heat treatment conditions only affected the heat affected zone cracking behaviour.

  • 36.
    Andersson, Joel
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser.
    Sjöberg, G.
    Brederholm, A.
    Hänninen, H.
    Solidification Cracking of Alloy Allvac 718Plus and Alloy 718 at Transvarestraint Testing2010Inngår i: EPD Congress 2008: Proceedings of Sessions and Symposia Sponsored by the Extraction and Processing Division (EPD) / [ed] Stanley M. Howard, Wiley-Blackwell, 2010, s. 157-169Konferansepaper (Fagfellevurdert)
  • 37.
    Andersson, Joel
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser.
    Sjöberg, G.
    Chaturvedi, M.
    Hot Ductility Study of Haynes 282 Superalloy2010Inngår i: Superalloy 718 and Derivatives: Proceedings of the 7th International Symposium on Superalloy 718 and Derivatives / [ed] E. A. Ott, J. R. Groh, A. Banik, I. Dempster, T. P. Gabb, R. Helmink, X. Liu, A. Mitchell, G. P. Sjöberg and A. Wusatowska-Sarnek, The Minerals, Metals, and Materials Society, 2010, s. 539-554Konferansepaper (Fagfellevurdert)
  • 38.
    Andersson, Joel
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser.
    Sjöberg, G.
    Hatami, S.
    Notch Sensitivity and Intergranular Crack Growth in the Allvac 718Plus Superalloy2007Inngår i: XVIII International Symposium on Air Breathing Engines (ISABE): Beijing, China, 2-7 September 2007, 2007, s. n.1293-Konferansepaper (Fagfellevurdert)
  • 39.
    Andersson, Joel
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser. Volvo Aero Corporation, Trollhättan, Sweden och Chalmers University of Technology, Gothenburg, Sweden.
    Sjöberg, G.
    Volvo Aero Corporation, Trollhättan, Sweden och Chalmers University of Technology, Gothenburg, Sweden.
    Hänninen, H.
    Aalto University School of Science and Technology, Espoo, Finland.
    Metallurgical Response of Electron Beam Welded Allvac® 718Plus™2011Inngår i: Hot Cracking Phenomena in Welds III / [ed] Lippold, J., Böllinghaus, T. and Cross C. E., Springer Berlin/Heidelberg, 2011, s. 415-428Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Electron beam welding of forged Allvac 718Plus superalloy has been carried out without any visible cracks in weld cross-sections. Healed cracks in the heat affected zone were, however, seen in most cross-sections with the healing as well as the cracking believed to be due to the constitutional liquation of the δ-phase. The δ-phase undergoes constitutional liquation in the Heat Affected Zone (HAZ) and consequently decreases the ductility of the material and renders cracks in the HAZ but due to the large amount of eutectic liquid produced at the same time the healing of the opened cracks takes place.

  • 40.
    Andersson, Joel
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser. Volvo Aero Corporation, Materials Technology Department, Trollhättan, Sweden och Chalmers University of Technology, Department of Materials and Manufacturing Technology, Göteborg,Sweden.
    Sjöberg, G.
    Volvo Aero Corporation, Materials Technology Department, Trollhättan, Sweden och Chalmers University of Technology, Department of Materials and Manufacturing Technology, Göteborg, Sweden.
    Larsson, J.
    Chalmers University of Technology, Department of Materials and Manufacturing Technology, Göteborg,Sweden.
    Investigation of Homogenization and its Influence on the Repair Welding of Cast Allvac 718Plus(®)2010Inngår i: Superalloy 718 and Derivatives: Proceedings of the 7th International Symposium on Superalloy 718 and Derivatives / [ed] E. A. Ott, J. R. Groh, A. Banik, I. Dempster, T. P. Gabb, R. Helmink, X. Liu, A. Mitchell, G. P. Sjöberg, and A. Wusatowska-Sarnek, The Minerals, Metals, and Materials Society, 2010, s. 439-454Konferansepaper (Fagfellevurdert)
  • 41.
    Andersson, Joel
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser. Department of Materials Technology, GKN Aerospace Engine Systems, Trollhättan, Sweden och Department of Materials and Manufacturing Technology, Chalmers University of Technology, Gothenburg, Sweden.
    Sjöberg, G.
    Department of Materials Technology, GKN Aerospace Engine Systems, Trollhättan, Sweden och Department of Materials and Manufacturing Technology, Chalmers University of Technology, Gothenburg, Sweden.
    Viskari, L.
    Department of Applied Physics, Chalmers University of Technology, Gothenburg, Sweden.
    Chaturvedi, M. C.
    Department of Mechanical and Industrial Engineering, University of Manitoba, Winnipeg, MB, Canada.
    Effect of Different Solution Heat Treatments on the Hot Ductility of Superalloys: Part 3 - Waspaloy2013Inngår i: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 29, nr 1, s. 43-53Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The susceptibility to heat affected zone cracking of Waspaloy has been investigated in terms of its hot ductility, measured as the reduction of area (RA). Gleeble testing with on-heating as well as on-cooling test cycles was carried out to illuminate the influence of different 4 h solution heat treatments between 996 and 1080°C. A ductility maximum of between 80 and 90%RA was found at 1050–1100°C for all conditions in the on-heating tests. Although the different heat treatment conditions showed similar macrohardness, the particle size and distribution of the γ′ and M23C6 phases differed, which significantly affected the on-heating ductility in the lower temperature test region. The ductile to brittle transition was initiated at 1100°C in the on-heating testing with indications of grain boundary liquation at the higher test temperatures. Ductility recovery, as measured in the on-cooling tests from 1240°C, was very limited with <30%RA for all conditions and test temperatures except for the 1080°C/4 h treatment, which exhibited 60%RA at 980°C.

  • 42.
    Andersson, Joel
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser. Department of Materials Technology, Volvo Aero Corporation, Trollhättan, Sweden and Department of Materials and Manufacturing Technology, Chalmers University of Technology, Gothenburg, Sweden.
    Sjöberg, G.
    Department of Materials Technology, Volvo Aero Corporation, Trollhättan, Sweden and Department of Materials and Manufacturing Technology, Chalmers University of Technology, Gothenburg, Sweden.
    Viskari, L.
    Department of Applied Physics, Chalmers University of Technology, Gothenburg, Sweden.
    Chaturvedi, M.C.
    Department of Mechanical and Industrial Engineering, University of Manitoba, Winnipeg, MB, Canada.
    Effect of different solution heat treatments on hot ductility of superalloys: Part 2 – Allvac 718Plus2012Inngår i: Materials Science and Technology, ISSN 0267-0836, Vol. 28, nr 6, s. 733-741Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The hot ductility of Allvac 718Plus for different solution heat treatments (954°C–15 h, 954°C–1 h, 982°C–1 h and 1050°C–3 h+954°C–1 h) has been investigated using Gleeble testing. Substantial variations in the microstructure among the heat treatments affected the Gleeble test hot ductility only to a very limited extent. Constitutional liquation of the NbC phase was found to be the main cause for the poor ductility at high testing temperatures in the on-heating cycle as well as at the lower temperatures on-cooling. Grain boundary δ phase was seen to assist the constitutional liquation of the NbC phase. Based on established evaluation criteria for Gleeble ductility testing, a ranked indicator for weldability is suggested.

  • 43.
    Andersson, Joel
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser. Department of Materials Technology at Volvo Aero Corporation, Trollhättan, and Chalmers University of Technology, Gothenburg, Sweden.
    Sjöberg, G.
    Department of Materials Technology at Volvo Aero Corporation, Trollhättan, and Chalmers University of Technology, Gothenburg, Sweden.
    Viskari, L.
    Department of Microscopy and Microanalysis at Chalmers University of Technology, 41296 Gothenburg, Sweden.
    Chaturvedi, M.C.
    Department of Mechanical and Industrial Engineering, University of Manitoba, Winnipeg, Manitoba, R3T 5V6 Canada.
    Effect of solution heat treatments on superalloys: Part 1 – alloy 7182012Inngår i: Materials Science and Technology, ISSN 0267-0836, Vol. 28, nr 5, s. 609-619Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The hot ductility as measured by Gleeble testing of Alloy 718 at four different solution heat treatments (954°C/15 h, 954°C/1 h, 982°C/1 h and 1050°C/3 h+954°C/1 h) has been investigated. It is concluded that constitutional liquation of NbC assisted by δ phase takes place and deteriorates the ductility. Parameters established by analysing the ductility dependence on temperature indicate a reduced weldability of the material in the coarse grain size state (ASTM 3) while indicating an increased weldability when containing a large amount of δ phase due to a grain boundary pinning effect. The accumulation of trace elements during grain growth at the highest temperature is believed to be the cause for the observed reduced on-cooling ductility.

  • 44.
    Andersson, Oscar
    et al.
    KTH Royal Institute of Technology, Department of Production Engineering and XPRES, Stockholm, Sweden.
    Fahlström, Karl
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW). Swerea Group .
    Melander, Arne
    KTH Royal Institute of Technology, Department of Production Engineering and XPRES, Stockholm, Sweden.
    Experiments and efficient simulations of distortions of laser beam-€“welded thin-sheet close beam steel structures2019Inngår i: Proceedings of the Institution of mechanical engineers. Part B, journal of engineering manufacture, ISSN 0954-4054, E-ISSN 2041-2975, Vol. 233, nr 3, s. 787-796Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this article, geometrical distortions of steel structures due to laser beam welding were analyzed. Two 700-mm-long U-beam structures were welded in overlap configurations: a double U-beam structure and a U-beam/flat structure. The structures were in different material combinations from mild steel to ultrahigh-strength steel welded with different process parameters. Different measures of distortions of the U-beam structures were evaluated after cooling. Significant factors of the welding process and the geometry of the structures were identified. Furthermore, welding distortions were modeled using two predictive finite element simulation models. The previously known shrinkage method and a newly developed time-efficient simulation method were evaluated. The new model describes the effects of expansion and shrinkage of the weld zone during welding and material plasticity at elevated temperatures. The new simulation method has reasonable computation times for industrial applications and improved agreement with experiments compared to the often used so-called shrinkage method. © 2018, IMechE 2018.

  • 45.
    Aragon Polanco, Gonzalo Eduardo
    Högskolan Väst, Institutionen för ingenjörsvetenskap.
    Inspection of welding electrodes using computer vision2022Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The use of computational methods to perform inspection tasks in the modern industry has increased in the last years, the fast response and repeatability are the key factor to define a standard in quality control. The visual inspection of components was in charge of highly skilled operators who were searching for defects or failures, but the complexity of the inspection triggered the necessity to migrate to a computational approach. This computer inspection system is composed of the hardware and the algorithm. The hardware includes the lighting and the camera, meanwhile, the algorithm works directly with the failure identification.

    In the welding industry, the SMAW (Shielded Metal Arc Welding) consists of using an electrode stick that is melted for the heat produced from an electro-voltaic arc between the electrode and the surface of the base metal. The quality of the welding depends on the quality of the electrode, that is why this project is focused on the visual inspection of the electrodes. The visual defects that compromise the welding quality can be fixed in two categories: the shape of the electrode and the texture of the surface. These two categories contemplate the existence of cracks, porosity and extrusion defects.

    The method which delivered the best results (94% of accuracy, 92% of repeatability) used a dark background, colour segmentation, image pre-processing (border enhancement), YOLO network for deep learning and image entropy performed in MATLAB. Additionally, the detection method allows identifying the position of the defects, their size and their type.The location of the defect is determined thanks to the division of the electrodes into smaller parts, if a failure is detected in one or more of them it is possible to know the position and the size of the defect. Meanwhile, the type of defect is the result of analysing the deep learning and entropy results. The collected failure data is presented in the inspection report, which has the potential to become a tool that could modify and enhance the manufacturing processes.

  • 46.
    Aranke, Omkar
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Effect of spray parameters on micro-structure and lifetime of suspension plasma sprayed thermal barrier coat-ings2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Fabrication of Thermal Barrier Coatings (TBCs) with higher lifetime and relatively cheaper processes is of particular interest for gas turbine applications. Suspension Plasma Spray (SPS) is capable of producing coatings with porous columnar structure, and it is also a much cheaper process compared to the conventionally used Electron Beam Physical Vapour Dep-osition (EB-PVD). Although TBCs fabricated using SPS have lower thermal conductivity as compared to other commonly used processes, they are still not commercialized due to their poor lifetime expectancy.

    Lifetime of TBCs is highly influenced by the top coat microstructure. The objective of this work was to study and evaluate the top coat microstructure produced using axial SPS with different process parameters. 8 wt. % Yttria Stabilized Zirconia (YSZ) suspension with 25 % solid load in ethanol was used to spray the top coat. The bond coat was deposited on Has-telloy-X substrates using a NiCoCrAlY powder by High Velocity Air Fuel (HVAF) spray with same process parameters. Influence of the microstructure on lifetime of the coatings was of particular interest in this work. The coating microstructure was analysed using Scanning Electron Microscope (SEM) and it was observed that axial SPS is capable of producing TBCs with varied top coat microstructure from highly porous to densely packed columnar microstructure. The lifetime of the coatings was determined by Thermal Cyclic Fatigue (TCF) testing and Burner Rig Testing (BRT). Porosity and Thermal conductivity of the coat-ings was determined by Image Analysis and Laser Flash Analysis (LFA) respectively.

    From the results obtained, it can be concluded that axial SPS could be a promising method of producing TBCs with low thermal conductivity & high lifetime for high temperature gas turbine applications.

  • 47.
    Aranke, Omkar
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Gupta, Mohit Kumar
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Markocsan, Nicolaie
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Li, Xin-Hai
    Siemens Industrial Turbomachinery AB, Finspång, Sweden.
    Kjellman, Björn
    GKN Aerospace Sweden AB, Trollhättan, Sweden.
    Microstructural Evolution and Sintering of Suspension Plasma-Sprayed Columnar Thermal Barrier Coatings2019Inngår i: Journal of thermal spray technology (Print), ISSN 1059-9630, E-ISSN 1544-1016, Vol. 28, nr 1-2, s. 198-211Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Suspension plasma spray (SPS) is capable of producing coatings with porous columnar structure, and it is also a much cheaper process compared to the conventionally used electron beam physical vapor deposition (EB-PVD). Although TBCs with a columnar microstructure that are fabricated using SPS have typically lower thermal conductivity than EB-PVD, they are used sparingly in the aerospace industry due to their lower fracture toughness and limited lifetime expectancy. Lifetime of TBCs is highly influenced by the topcoat microstructure. The objective of this work was to study the TBCs produced using axial SPS with different process parameters. Influence of the microstructure on lifetime of the coatings was of particular interest, and it was determined by thermal cyclic fatigue testing. The effect of sintering on microstructure of the coatings exposed to high temperatures was also investigated. Porosity measurements were taken using image analysis technique, and thermal conductivity of the coatings was determined by laser flash analysis. The results show that axial SPS is a promising method of producing TBCs having various microstructures with good lifetime. Changes in microstructure of topcoat due to sintering were seen evidently in porous coatings, whereas dense topcoats showed good resistance against sintering.

    Fulltekst (pdf)
    fulltext
  • 48.
    Ariaseta, Achmad
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV). Department of Metallurgical Engineering, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (IDN).
    Khan, Abdul Khaliq
    Manitoba Institute for Materials, University of Manitoba, Winnipeg (CAN).
    Andersson, Joel
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Ojo, Olanrewaju
    Department of Mechanical Engineering, University of Manitoba, Winnipeg (CAN).
    Microstructural study of keyhole TIG welded nickel-based superalloy G272023Inngår i: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 204, artikkel-id 113178Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The weld fusion zone (FZ) microstructure obtained after keyhole tungsten inert gas welding and post-weld solution heat treatments (PWSHTs) of a new nickel (Ni)-based superalloy called G27 is studied, and the grain growth behavior in the base material (BM) during PWSHTs is characterized. Microsegregation-induced interdendritic microconstituents in the FZ of as-welded G27 are identified by analytical (scanning) transmission electron microscopy ((S)TEM) as niobium (Nb)-rich MC carbides, Nb-rich Laves eutectic constituents, γ’ and η phases. The Laves eutectics are generally considered brittle and can adversely affect the mechanical properties of the weldment; thus, an hour PWSHTs were performed at 954 °C–1060 °C to eliminate the γ/Laves eutectics. PWSHT up to 1010 °C results in only partial removal of Laves eutectics with an excessive formation of η phase surrounding the Laves phase. Complete dissolution of Laves eutectics with no η phase formation is achieved after a PWSHT is performed at 1060 °C. Relative to INCONEL® alloy 718, the complete elimination of the γ/Laves eutectic constituents in the FZ of G27 through a PWSHT was proven to be achieved without causing excessive grain growth in the BM, which could be due to the pinning effect of the fine molybdenum (Mo)-rich precipitates, that are formed during solution heat treatment and identified as hexagonal close-packed phase particles through extensive (S)TEM analyses.

    Fulltekst (pdf)
    fulltext
  • 49.
    Ariaseta, Achmad
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Pick, Dario
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Andersson, Joel
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Ojo, Olanrewaju
    Department of Mechanical Engineering, University of Manitoba, Winnipeg (CAN).
    Keyhole TIG Welding of New Co-Lean Nickel-Based Superalloy G272023Inngår i: Proceedings of the 10th International Symposium on Superalloy 718 and Derivatives / [ed] Eric A. Ott, Joel Andersson, Chantal Sudbrack, Zhongnan Bi, Kevin Bockenstedt, Ian Dempster, Michael Fahrmann, Paul Jablonski, Michael Kirka, Xingbo Liu, Daisuke Nagahama, Tim Smith, Martin Stockinger, Andrew Wessman, Springer Cham , 2023, s. 807-824Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The influence of keyhole TIG (K-TIG) welding parameters on the weld geometry and defects of a new Co-lean nickel-based superalloy G27 was studied, and the microstructures of the heat-affected zone (HAZ) and fusion zone (FZ) of the K-TIG-welded Alloy G27 were characterized. No cracks are found in the FZ and HAZ. Minimum weld width and face underfill statistically were significantly influenced by travel speed and interaction current*travel speed. Root excess weld metal was only significantly influenced by travel speed. Face excess weld metal was significantly influenced by all the factors, including their interaction. On the other hand, all the factors, including their interaction, did not significantly influence the average pore diameter. In the FZ microstructure, interdendritic microconstituents are identified as (Nb, Ti)C particles and γ/Laves eutectic constituents. In addition, a plate-like phase is observed surrounding the Laves phase, and γʹ precipitates are found to be inhomogeneously precipitated in the FZ. In the partially melted zone (PMZ), (Nb, Ti)C, Laves phase, γʹ precipitates, and plate-like particles are found in the liquated and resolidified regions, suggesting the solidification behavior in PMZ is likely to follow a similar pattern to the one observed in FZ.

  • 50.
    Ariaseta, Achmad
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV). Department of Metallurgical Engineering, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (IDN).
    Pick, Dario
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Andersson, Joel
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Ojo, Olanrewaju
    Department of Mechanical Engineering, University of Manitoba, Winnipeg, MB R3T 5V6 (CAN).
    Study of Pulsed Laser Beam Welding of Nickel-Based Superalloy G272024Inngår i: Sustainable Production through Advanced Manufacturing, Intelligent Automation and Work Integrated Learning: Proceedings of the 11th Swedish Production Symposium (SPS2024) / [ed] Joel Andersson, Shrikant Joshi, Lennart Malmsköld, Fabian Hanning, IOS Press , 2024, s. 39-49Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    The influence of pulsed laser beam welding (LBW) parameters on the weld geometry and imperfections of a new nickel-based superalloy called G27 was studied by a statistical design of experiment, and the microstructures of the weld fusion zone (FZ) of the pulsed laser beam-welded G27 were characterized. No evidence of cracks is found in the FZ and heat-affected zone (HAZ). Other weld imperfections, such as undercut and underfill, were also hardly observed.

    The pulse factor significantly influenced all the responses, i.e., minimum weld width (Wm), root excess weld metal, and average pore diameter, whereas welding travel speed significantly influenced Wm and root excess weld metal. Power and interaction between pulse frequency*pulse factor were statistically significant in influencing the root excess weld metal and average pore diameter, respectively. The pulse frequency and interactions between power*travel speed, power*pulse factor, power*pulse frequency, travel speed*pulse factor, and travel speed*pulse frequency did not significantly influence any response.

    Microsegregation pattern that occurs during weld solidification leads to the formation of Nb-rich MC carbides and Nb-rich Laves phase as the major secondary phase constituents in the FZ of as-welded G27. The presence of brittle Laves phase requires careful consideration when developing suitable post-weld heat treatment of G27.

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