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  • 1.
    Alvi, Sajid
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Luleå, Sweden.
    Neikter, Magnus
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Luleå University of Technology, Department of Engineering Sciences and Mathematics, Luleå, Sweden.
    Antti, Marta -Lena
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Luleå, Sweden.
    Akhtar, Farid
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Luleå, Sweden.
    Tribological performance of Ti6Al4V at elevated temperatures fabricated by electron beam powder bed fusion2021Inngår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 153, artikkel-id 106658Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electron beam powder bed fusion (EBPBF) is a beneficial processing route to fabricate Ti6Al4V alloy for aerospace applications due to its relatively low lead time and the possibility of topology optimization. The dry sliding wear behavior of EBPBF-Ti6Al4V against steel- and alumina-counterballs from room temperature (RT) to 500 °C was investigated to evaluate the influence of EBPBF processing and microstructure on the wear properties for broadening the application criteria of this lightweight alloy. The wear tests revealed that the wear rate decreased with increasing temperature due to formation of stable oxide glaze layer. This study reveals elevated temperature sliding wear behavior, wear mechanisms and microstructural changes below the wear track of EBPBF Ti6Al4V alloy against steel and alumina counterbodies. 

  • 2.
    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. 

  • 3.
    Edin, Emil
    et al.
    Division of Materials Science, Luleå University of Technology, Luleå (SWE).
    Svahn, F.
    GKN Aerospace Sweden AB, 46181, Trollhättan (SWE).
    Neikter, Magnus
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Åkerfeldt, P.
    Division of Materials Science, Luleå University of Technology, Luleå (SWE).
    Stress relief heat treatment and mechanical properties of laser powder bed fusion built 21-6-9 stainless steel2023Inngår i: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 868, artikkel-id 144742Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, the effectiveness of residual stress relief annealing on a laser powder bed fusion (L-PBF) manufactured austenitic stainless steel, alloy 21-6-9 was investigated. Residual stress levels were gauged using geometrical distortion and relaxation testing results. In the investigated temperature interval (600–850 °C), shape stability was reached after subjecting the as-built material to an annealing temperature of 850 °C for 1 h. Microstructural characterization and tensile testing were also performed for each annealing temperature to evaluate the alloy’s thermal stability and the resulting tensile properties. In the as-built state, a yield strength (YS) of 640 MPa, ultimate tensile strength (UTS) of 810 MPa and 4D elongation of 47% were measured. Annealing at 850 °C for 1 h had little measurable effect on ductility (48% 4D elongation) while still having a softening effect (UTS = 775 MPa, YS = 540 MPa). From the microstructural characterization, cell-like features were observed sporadically in the annealed condition and appeared stable up until 800 °C after which gradual dissolution began, with the last remnants disappearing after subjecting the material to 900 °C for 1 h. © 2023 The Authors

    Fulltekst (pdf)
    fulltext
  • 4.
    Goel, Sneha
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Neikter, Magnus
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Capek, J.
    Paul Scherrer Institute, Laboratory for Neutron Scattering and Imaging, , Villigen PSI, CH-5232, Switzerland (CHE).
    Polatidis, Efthymios
    Paul Scherrer Institute, Laboratory for Neutron Scattering and Imaging, , Villigen PSI, CH-5232, Switzerland (CHE).
    Colliander, Magnus Hörnqvist
    Chalmers University of Technology, Gothenburg, 41296, Sweden .
    Joshi, Shrikant V.
    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).
    Residual stress determination by neutron diffraction in powder bed fusion-built Alloy 718: Influence of process parameters and post-treatment2020Inngår i: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 195, artikkel-id 109045Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Alloy 718 is a nickel-based superalloy that is widely used as a structural material for high-temperature applications. One concern that arises when Alloy 718 is manufactured using powder bed fusion (PBF) is that residual stresses appear due to the high thermal gradients. These residual stresses can be detrimental as they can degrade mechanical properties and distort components. In this work, residual stresses in PBF built Alloy 718, using both electron and laser energy sources, were measured by neutron diffraction. The effects of process parameters and thermal post-treatments were studied. The results show that thermal post-treatments effectively reduce the residual stresses present in the material. Moreover, the material built with laser based PBF showed a higher residual stress compared to the material built with electron-beam based PBF. The scanning strategy with the lower amount of residual stresses in case of laser based PBF was the chessboard strategy compared to the bi-directional raster strategy. In addition, the influence of measured and calculated lattice spacing (d0) on the evaluated residual stresses was investigated. © 2020 The Authors

  • 5.
    Heidarzadeh, Akbar
    et al.
    Department of Materials Engineering, Azarbaijan Shahid Madani University, Tabriz (IRN).
    Neikter, Magnus
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Enikeev, Nariman
    Saint Petersburg State University, 7/9 Universitetskaya Nab., St. Petersburg (RUS); Ufa State Aviation Technical University, K. Marx 12, Ufa (RUS).
    Cui, Luqing
    Division of Engineering Materials, Department of Management and Engineering, Linköping University, Linköping (SWE).
    Forouzan, Farnoosh
    Department of Engineering Sciences and Mathematics, Luleå University of Technology, SE-97187 Luleå, (SWE).
    Mousavian, Reza Taherzadeh
    I-Form, Advanced Manufacturing Research Centre, Dublin City University, Dublin (IRL).
    Post-treatment of additively manufactured Fe-Cr-Ni stainless steels by high pressure torsion: TRIP effect2021Inngår i: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 811, artikkel-id 141086Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High pressure torsion (HPT) at room temperature was used for post-treatment of additively manufactured Fe?Cr?Ni stainless steel with 12.9 wt % Ni as a very strong austenite stabilizer. The results showed that HPT caused a considerable increase in nanohardness of the additively manufactured samples. In contrast with thermodynamic equilibrium-state modeling, a phase transformation from FCC to HCP structure occurred, leading to the formation of ?-martensite during HPT on high angle boundaries, low angle boundaries, and dislocation cells with no detection of deformation twins. It was demonstrated that the combination of additive manufacturing thanks to the high density of dislocations after solidification and HPT process expands the opportunities of both methods to control deformation mechanisms in stainless steels leading to different phase and microstructural features. Thus, the outcome of this study provides a fundamental basis to design advanced structural materials.

  • 6.
    Karimi Neghlani, Paria
    et al.
    a Multi-Scale Additive Manufacturing Lab, Department of Mechanical and Mechatronics Engineering, University of Waterloo (CAN).
    Thalavai Pandian, Karthikeyan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Neikter, Magnus
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Processing of high-performance materials by electron beam-powder bed fusion2023Inngår i: Additive Manufacturing of High-Performance Metallic Materials / [ed] Pederson, Robert,Andersson, Joel & Joshi, Shrikant V., Elsevier, 2023, 1., s. 103-181Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Electron beam-powder bed fusion (EB-PBF) is a process that uses a highly intense electron beam to melt metallic powders to create parts. In comparison to a conventional process, EB-PBF is more efficient at producing customized and specific parts in industries such as aerospace, space, and medical. Additionally, the EB-PBF process is used to manufacture highly complex parts for which other technologies would be prohibitively expensive or difficult to apply; increased geometric complexity does not necessarily imply increased cost. However, because the interaction of the electron beam with the powder and substrate material is complex, a high level of knowledge is required to master the skill of producing structurally sound components. This chapter discusses crucial features of the process parametermicrostructure-defect relationship that must be taken into Electron beam-powder bed fusion (EB-PBF) is a process that uses a highly intense electron beam to melt metallic powders to create parts. In comparison to a conventional process, EB-PBF is more efficient at producing customized and specific parts in industries such as aerospace, space, and medical. Additionally, the EB-PBF process is used to manufacture highly complex parts for which other technologies would be prohibitively expensive or difficult to apply; increased geometric complexity does not necessarily imply increased cost. However, because the interaction of the electron beam with the powder and substrate material is complex, a high level of knowledge is required to master the skill of producing structurally sound components. This chapter discusses crucial features of the process parametermicrostructure-defect relationship that must be taken into account in order to generate sufficiently sound builds of highperformance materials employing EB-PBF.

  • 7.
    Mahade, Satyapal
    et al.
    GKN Aerospace, Trollhättan (SWE).
    Bhattacharya, Prajina
    GKN Aerospace, Trollhättan (SWE).
    Tolvanen, Sakari
    GKN Aerospace, Trollhättan (SWE).
    Pederson, Robert
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Neikter, Magnus
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Processing of high-performance materials by laser directed energy deposition with wire2023Inngår i: Additive Manufacturing of High-Performance metallic Materials / [ed] Pederson, Robert, Andersson, Joel & Joshi, Shrikant V., Elsevier, 2023, 1., s. 260-305Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Processing of metallic materials by Laser Directed Energy Deposition (LDED), with Wire (w) as the feedstock, enables the manufacturing of high precision, near-net shape components that require minimal postmachining, without compromising the performance. L-DEDw has also shown the capability to add intricate features on large structures, which makes it an attractive fabrication technique for aerospace application. The key merits of wire as the feedstock when compared to powder include; higher deposition rates, low porosity in the deposited material, excellent surface finish, and, ∼ 100% utilization of the feedstock. However, despite the attractive merits, the difference in solidification rates during L-DEDw processing when compared to other fabrication routes could induce high residual stresses, which can be detrimental to the integrity of cracksensitive alloys. Additionally, there exists an inherent challenge during L-DEDw fabrication, where controlling the process variables to ensure stable deposition conditions becomes essential to achieve repeatable, and desired results. The recent advancements in the area of monitoring and control systems, and their integration with L-DEDw processing, have enabled to overcome the processing instability related challenges. Furthermore, different L-DEDw processing strategies for alleviating residual stresses (tensile) accumulation in the deposits are discussed, which could enable defectfree, high-performance component fabrication. Although the utilization of L-DEDw for processing diverse alloy systems has been explored in the literature, the current chapter's scope is restricted to L-DEDw processing of Nickel-based and Titanium-based alloys, which are often utilized in the aeroengine. This work aims to provide a holistic perspective and shed light on the state-of-the-art, recent developments, sustainability aspects and future directions for L-DEDw processed, highperformance Ni-based and Ti-based alloys.

  • 8.
    Neikter, Magnus
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Bhaskar, P.
    Högskolan Väst, Institutionen för ingenjörsvetenskap.
    Singh, S.
    Joining and Welding Research Institute, Osaka University, Osaka (JPN).
    Kadoi, K.
    Joining and Welding Research Institute, Osaka University, Osaka (JPN).
    Lyphout, Christophe
    Research Institutes of Sweden, Gothenburg (SWE).
    Svahn, F.
    GKN Aerospace Sweden AB, Trollhättan (SWE).
    Pederson, Robert
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Tensile properties of laser powder bed fusion built JBK-75 austenitic stainless steel2023Inngår i: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 874, artikkel-id 144911Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Laser powder bed fusion (PBF-LB) is an additive manufacturing (AM) process that has several advantages to conventional manufacturing, such as near net-shaping capabilities and reduced material wastage. To be able to manufacture a novel material, however, one needs to first optimize the process parameters, to decrease porosity content as low as possible. Therefore, in this work the process parameters of PBF-LB built JBK-75 austenitic stainless steel, and its influence on porosity, microstructure, and hardness have been investigated. The least amount of porosity was found by using 132 W laser power, 750 mm/s scan speed, layer thickness 30 μm, and 0.12 mm hatch distance. These process parameters were then used to manufacture material for tensile testing, to investigate the tensile properties of PBF-LB built JBK-75 and potential anisotropic behavior. Hot isostatic pressing (HIP) was also performed in two sets of samples, to investigate the effect of pore closure on the tensile properties. The ultimate tensile strength (UTS) for the un-HIPed specimens was 1180 (horizontally built) and 1110 (vertically built) MPa. For the HIPed specimens, it was 1160 (horizontally built) and 1100 (vertically built) MPa. The anisotropic presence was explained by the presence of texture, with a multiple of random distribution (MRD) up to 4.34 for the {001} planes, and defects.

  • 9.
    Neikter, Magnus
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Luleå University of Technology, Division of Materials Science, Luleå, 97181, Sweden;Chalmers University of Technology, .
    Colliander, Magnus
    Chalmers University of Technology,Department of Applied Physics, Göteborg, 41296, Sweden.
    de Andrade Schwerz, C.
    GKN Aerospace Engine Systems, Trollhättan, 46138, Sweden.
    Hansson, Thomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). GKN Aerospace Engine Systems, Trollhättan, 46138, Sweden.
    Åkerfeldt, Pia
    Luleå University of Technology, Division of Materials Science, Luleå, 97181, Sweden.
    Pederson, Robert
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Antti, Marta-Lena
    Luleå University of Technology, Division of Materials Science, Luleå, 97181, Sweden.
    Fatigue crack growth of electron beam melted TI-6AL-4V in high-pressure hydrogen2020Inngår i: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 13, nr 6, artikkel-id 1287Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Titanium-based alloys are susceptible to hydrogen embrittlement (HE), a phenomenon that deteriorates fatigue properties. Ti-6Al-4V is the most widely used titanium alloy and the effect of hydrogen embrittlement on fatigue crack growth (FCG) was investigated by carrying out crack propagation tests in air and high-pressure H2 environment. The FCG test in hydrogen environment resulted in a drastic increase in crack growth rate at a certain DK, with crack propagation rates up to 13 times higher than those observed in air. Possible reasons for such behavior were discussed in this paper. The relationship between FCG results in high-pressure H2 environment and microstructure was investigated by comparison with already published results of cast and forged Ti-6Al-4V. Coarser microstructure was found to be more sensitive to HE. Moreover, the electron beam melting (EBM) materials experienced a crack growth acceleration in-between that of cast and wrought Ti-6Al-4V. © 2020 by the authors.

    Fulltekst (pdf)
    fulltext
  • 10.
    Neikter, Magnus
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Edin, Emil
    Division of Materials Science, Luleå University of Technology, 97187 Luleå (SWE).
    Proper, Sebastian
    esearch Institutes of Sweden, 41314 Gothenburg (SWE).
    Bhaskar, Phavan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Nekkalapudi, Gopi Krishna
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Linde, Oscar
    GKN Aerospace Sweden AB, 46181 Trollhättan (SWE).
    Hansson, Thomas
    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).
    Tensile Properties of 21-6-9 Austenitic Stainless Steel Built Using Laser Powder-Bed Fusion2021Inngår i: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 14, nr 15, artikkel-id 4280Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Alloy 21-6-9 is an austenitic stainless steel with high strength, thermal stability at high temperatures, and retained toughness at cryogenic temperatures. This type of steel has been used for aerospace applications for decades, using traditional manufacturing processes. However, limited research has been conducted on this alloy manufactured using laser powder-bed fusion (LPBF). Therefore, in this work, a design of experiment (DOE) was performed to obtain optimized process parameters with regard to low porosity. Once the optimized parameters were established, horizontal and vertical blanks were built to investigate the mechanical properties and potential anisotropic behavior. As this alloy is exposed to elevated temperatures in industrial applications, the effect of elevated temperatures (room temperature and 750 degrees C) on the tensile properties was investigated. In this work, it was shown that alloy 21-6-9 could be built successfully using LPBF, with good properties and a density of 99.7%, having an ultimate tensile strength of 825 MPa, with an elongation of 41%, and without any significant anisotropic behavior.

    Fulltekst (pdf)
    fulltext
  • 11.
    Neikter, Magnus
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Raja, D. C.
    Division of mechanical engineering, Vellore Institute of Technology, Vellore (IND).
    Balachandramurthi, Arun Ramanathan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Harlin, P.
    Sandvik Additive Manufacturing, Sandviken (SWE).
    Tailored ductility and strength for enhanced impact toughness of laser powder fusion built Alloy 7182021Inngår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 884, artikkel-id 161374Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Impact toughness of Alloy 718 built via laser powder bed fusion (LPBF) in as-built and thermally post treated conditions were investigated. The effect of various stages in the thermal post-treatment, including stress relief, hot isostatic pressing, solution treatment, and aging on the microstructure, texture, ductility, hardness, and impact toughness were studied. The greatest impact toughness was found in the as-built Alloy 718 material, associated with the high ductility of the material. The ductility results were also inversely related to the hardness of the investigated materials. Where the material with the highest ductility had the lowest hardness etc. Anisotropy in the impact toughness behavior was present in the as-built and post-heat treated specimens, which was explained by the presence of texture in all of the investigated material. With the applied heat treatments, recrystallization occurred and the preferential crystal orientations were randomized, decreasing the texture. The thermal post-treating conditions rendered different types of microstructures, with various grain sizes. The carbide content remained the same for the three investigated thermal post-treating conditions. 

    Fulltekst (pdf)
    Journal of Alloys and Compounds
  • 12.
    Pederson, Robert
    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).
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Neikter, Magnus
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Isoaho, Jerry
    GKN Aerospace Engine Systems,Trollhättan (SWE).
    Metal additive manufacturing: Motivation, process portfolio, and application potential2023Inngår i: Additive Manufacturing of High-Performance metallic Materials / [ed] Pederson, Robert, Andersson, Joel & Joshi, Shrikant V., Elsevier, 2023, 1, s. 20-40Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    The idea of adding material only where needed to manufacturesolid metallic high-performing components is intriguing andone of the main reasons for the great interest in additivemanufacturing (AM) around the world. Especially whensustainability comes into play, as in recent times more thanever, AM technology is most appropriate since it enables almostfull material utilization with minimal waste. From an economicstandpoint, this becomes particularly advantageous for moreexpensive materials such as superalloys and titanium alloys.However, the route of going from a CAD drawing of a part to anadditively manufactured final component that is qualified and inserial production involves numerous challenges. The intentionof this book is to shed light on and explain some of theassociated challenges beginning with the importance of thestarting material and how it is manufactured, i.e., wire orpowder, continuing into description of the conventional andPederson, R., Andersson, J., & Joshi, S. (2023). Additive manufacturing of high-performance metallic materials. Elsevier.Created from vast-ebooks on 2024-01-08 16:09:20. Copyright © 2023. Elsevier. All rights reserved.most commonly used AM processes, followed by postbuildtreatments and nondestructive evaluations, to eventuallyproduce the final part with mechanical performance consistentwith the application requirements. In the end, selected realindustry examples of AM parts for actual applications will bepresented

  • 13.
    Raza, Tahira
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Adegoke, Olutayo
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Siemens Energy, Finspång (SWE).
    Squillaci, Linda
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). GKN Aerospace Engine Systems, Trollhättan (SWE).
    Neikter, Magnus
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Processing of high-performancematerials by laser beam-powderbed fusion2023Inngår i: Additive Manufacturing of High-Performance Metallic Materials / [ed] Pederson, Robert, Andersson, Joel & Joshi, Shrikant V., Elsevier, 2023, 1., s. 182-229Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Processing of high-performance materials by laser beam powder bed fusion (LB-PBF) provides an alternative manufacturing route to, i.e., investment casting and is suitable for production of high-performance materials having complex geometry such as turbine blades. The main benefit of powder bed fusion in general is associated with the fact that increased geometrical complexity does not add any cost. However, the processability of the alloys of interest is closely linked to process parameters where highperformance materials belong to a special class of materials that need substantial attention to avoid problems, not at least with regard to different types of cracking. In this chapter, the relationship between process parameter-microstructure-defect relationship will be discussed and analyzed.

  • 14.
    Segerstark, Andreas
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Neikter, Magnus
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Processing of high-performance materials by laser-directed energy deposition with powders2023Inngår i: Additive Manufacturing of High-Performance metallic Materials / [ed] Pederson, Robert, Andersson, Joel & Joshi, Shrikant V., Elsevier, 2023, 1., s. 230-259Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Processing of high-performance materials by Directed Energy Deposition with Powders (L-DED-P) is frequently utilized in repair as well as remanufacturing apart from manufacturing. One benefit of the process is the low heat input in comparison to, i.e., L-DED with wire which is preferable regarding residual stresses and distortion. However, care must be taken to minimize defects that are at stake in forming if process parameters are not adequately adapted to the specific application. There is a strong correlation between the process parameters and metallurgical behavior which in turn give rise to potential defects and the final performance of the part to be produced. This chapter gives an overview of the processmicrostructure-defect relations that are of importance in L- DED-P processing.

  • 15.
    Squillaci, Linda
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Neikter, Magnus
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Hansson, Thomas
    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).
    Niklasson, Fredrik
    GKN Aerospace, Trollhättan (SWE).
    Pederson, Robert
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Extending powder particle size distribution of laser powder bed fusion Ti-6Al-4V: investigation of single tracks and multilayer experiments2023Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    This paper explores the effects of varying process parameters (i.e., laser power, laser scanning speed, hatch distance) on the characteristics of single tracks, triple tracks and cubes, in order to provide answers to Research Question 1. A full factorial DoE approach was adopted to produce the experiments. Data was extracted from different sources to find correlations between tracks and multilayer geometries. A digital microscope was used to obtain height profiles, whilst polished/etched cross sections cut parallel to the build direction were imaged using a LOM to obtain measurements of track height, width, melt pool depth, subsurface porosity and residual defect content in cubes. Track height was found to exceed the recoated value of 70μm for both single and triple tracks. The width of single tracks showed a clear upward trend when displayed against VED, showing a lateral expansion as energy input increased. It was also revealed that single tracks expand laterally as they grow above the substrate, indicating swelling. The melt pool depth showed a steady upward trend when plotted against LED, though less systematic than track width. A martensitic microstructure was detected, with hierarchical α’ needles growing at prescribed crystallographic directions within vertical prior-β grains. A large portion of spatter particles and unmelted powder granules were detected on the substrate and tracks, with many accumulating on the side of the tracks forming a denudation zone.

  • 16.
    Thalavai Pandian, Karthikeyan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Neikter, Magnus
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Bahbou, F.
    GE Additive, SE-435 33 Mölnlycke (SWE).
    Ganvir, A.
    GKN Aerospace Engine Systems, Trollhättan (SWE).
    Hansson, Thomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). GKN Aerospace Engine Systems, Trollhättan (SWE).
    Pederson, Robert
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Fatigue behavior of low-temperature hot isostatic pressed electron beam powder bed fusion manufactured Ti-6Al-4 V2023Inngår i: Journal of Alloys and Compounds, ISSN 0925-8388, Vol. 962, artikkel-id 171086Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ti-6Al-4 V finds application in the fan and compressor modules of gas turbine engines due to its high specific strength. Ti-6Al-4 V components manufactured using one of the additive manufacturing (AM) techniques, the electron beam powder bed fusion (PBF-EB) process, has been an active area of research in the past decade. The fatigue life of such PBF-EB built Ti-6Al-4 V components is improved by hot isostatic pressing (HIP) treatment typically performed at about 920 ˚C. The HIP treatment at 920 ˚C results in coarsening of α laths and reduced static strength and therefore a low-temperature HIP treatment is performed at about 800 ˚C to limit the impact on static mechanical properties. In the present work, the low cycle fatigue and fatigue crack growth behavior of such a modified HIP (low-temperature HIP) treated material is assessed and compared with the respective data for the standard HIP-treated material. The modified HIP-treated material has fatigue performance comparable to the standard HIP-treated material. This work suggests that the modified HIP treatment improves the static mechanical properties without significantly impacting the fatigue performance. Also, fatigue life predictions were made from the measured defect size at the crack initiation site using a linear elastic fracture mechanics tool. The life predictions show good agreement with the experimental values for defects greater than the intrinsic crack length, where life is well predicted by large-crack growth methodology. 

    Fulltekst (pdf)
    fulltext
  • 17.
    Thalavai Pandian, Karthikeyan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Neikter, Magnus
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Bahbou, Fouzi
    GE Additive, 435 33 Molnlycke (SWE).
    Hansson, Thomas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). GKN Aerospace Engine Systems, 461 38 Trollhattan, (SWE).
    Pederson, Robert
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Elevated-Temperature Tensile Properties of Low-Temperature HIP-Treated EBM-Built Ti-6Al-4V.2022Inngår i: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 15, nr 10, artikkel-id 3624Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Evaluation of the high-temperature tensile properties of Ti-6Al-4V manufactured by electron beam melting (EBM) and subjected to a low-temperature hot isostatic pressing (HIP) treatment (800 °C) was performed in this study. The high-temperature tensile properties of as-built and standard HIP-treated (920 °C) materials were studied for comparison. Metallurgical characterization of the as-built, HIP-treated materials was carried out to understand the effect of temperature on the microstructure. As the HIP treatments were performed below the β-transus temperature (995 °C for Ti-6Al-4V), no significant difference was observed in β grain width between the as-built and HIP-treated samples. The standard HIP-treated material measured about 1.4×-1.7× wider α laths than those in the modified HIP (low-temperature HIP)-treated and as-built samples. The standard HIP-treated material showed about a 10-14% lower yield strength than other tested materials. At 350 °C, the yield strength decreased to about 65% compared to the room-temperature strength for all tested specimens. An increase in ductility was observed at 150 °C compared to that at room temperature, but the values decreased between 150 and 350 °C because of the activation of different slip systems.

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