Endre søk
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Influence of build layout and orientation on microstructural characteristics of electron beam melted Alloy 718
Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). (PTW)ORCID-id: 0000-0001-6610-1486
Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). (PTW)ORCID-id: 0000-0002-7663-9631
Linköping University, Division of Engineering Materials, Department of Management and Engineering, Linköping, 581 83, Sweden.
University of Chalmers, Division of Materials and Manufacture, Industrial and Materials Science, Gothenburg, 412 96, Sweden.
Vise andre og tillknytning
2018 (engelsk)Inngår i: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 99, nr S1, s. 2903-2913Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Effects of build layout and orientation consisting of (a) height from the build plate (Z-axis), (b) distance between samples, and (c) location in the build plate (X-Y plane) on porosity, NbC fraction, and hardness in electron beam melted (EBM) Alloy 718 were studied. The as-built samples predominantly showed columnar structure with strong ˂001˃ crystallographic orientation parallel to the build direction, as well as NbC and ÎŽ-phase in inter-dendrites and grain boundaries. These microstructural characteristics were correlated with the thermal history, specifically cooling rate, resulted from the build layout and orientation parameters. The hardness and NbC fraction of the samples increased around 6% and 116%, respectively, as the height increased from 2 to 45 mm. Moreover, by increasing the height, formation of ÎŽ-phase was also enhanced associated with lower cooling rate in the samples built with a greater distance from the build plate. However, the porosity fraction was unaffected. Increasing the sample gap from 2 to 10 mm did not change the NbC fraction and hardness; however, the porosity fraction increased by 94%. The sample location in the build chamber influenced the porosity fraction, particularly in interior and exterior areas of the build plate. The hardness and NbC fraction were not dependent on the sample location in the build chamber. © 2018, The Author(s).

sted, utgiver, år, opplag, sider
2018. Vol. 99, nr S1, s. 2903-2913
Emneord [en]
3D printers, Cooling, Electron beam melting, Electron beams, Grain boundaries, Hardness, Location, Niobium compounds, Porosity, Alloy 718, Build direction, Columnar structures, Crystallographic orientations, Micro-structural characteristics, Micro-structural characterization, Orientation parameter, Sample location, Porous plates
HSV kategori
Forskningsprogram
TEKNIK, Produktions- och materialteknik; Produktionsteknik
Identifikatorer
URN: urn:nbn:se:hv:diva-13043DOI: 10.1007/s00170-018-2621-6ISI: 000452076900065Scopus ID: 2-s2.0-85053670925OAI: oai:DiVA.org:hv-13043DiVA, id: diva2:1259278
Forskningsfinansiär
European Regional Development Fund (ERDF)Knowledge Foundation
Merknad

First Online: 17 September 2018

Tilgjengelig fra: 2018-10-29 Laget: 2018-10-29 Sist oppdatert: 2020-11-10bibliografisk kontrollert
Inngår i avhandling
1. Electron beam melting of Alloy 718: Influence of process parameters on the microstructure
Åpne denne publikasjonen i ny fane eller vindu >>Electron beam melting of Alloy 718: Influence of process parameters on the microstructure
2018 (engelsk)Licentiatavhandling, med artikler (Annet vitenskapelig)
Abstract [en]

Additive manufacturing (AM) is the name given to the technology of building 3D parts by adding layer-by-layer of materials, including metals, plastics, concrete, etc. Of the different types of AM techniques, electron beam melting (EBM), as a powder bed fusion technology, has been used in this study. EBM is used to build parts by melting metallic powders by using a highly intense electron beam as the energy source. Compared to a conventional process, EBM offers enhanced efficiency for the production of customized and specific parts in aerospace, space, and medical fields. In addition, the EBM process is used to produce complex parts for which other technologies would be either expensive or difficult to apply. This thesis has been divided into three sections, starting from a wider window and proceeding to a smaller one. The first section reveals how the position-related parameters (distance between samples, height from build plate, and sample location on build plate) can affect the microstructural characteristics. It has been found that the gap between the samples and the height from the build plate can have significant effects on the defect content and niobium-rich phase fraction. In the second section, through a deeper investigation, the behavior of Alloy 718 during the EBM process as a function of different geometry-related parameters is examined by building single tracks adjacent to each other (track-by-track) andsingle-wall samples (single tracks on top of each other). In this section, the main focus is to understand the effect of successive thermal cycling on microstructural evolution. In the final section, the correlations between the main machine-related parameters (scanning speed, beam current, and focus offset) and the geometrical (melt pool width, track height, re-melted depth, and contact angle) and microstructural (grain structure, niobium-rich phase fraction, and primary dendrite arm spacing) characteristics of a single track of Alloy 718 have been investigated. It has been found that the most influential machine-related parameters are scanning speed and beam current, which have significant effects on the geometry and the microstructure of the single-melted tracks.

sted, utgiver, år, opplag, sider
Trollhättan: University West, 2018. s. 65
Serie
Licentiate Thesis: University West ; 22
Emneord
Additive manufacturing; Powder bed fusion; Electron beam melting; Part’s orientation; Microstructure development; Single track; Energy input; Focus offset; Geometrical features, Alloy 718
HSV kategori
Forskningsprogram
TEKNIK, Produktions- och materialteknik; Produktionsteknik
Identifikatorer
urn:nbn:se:hv:diva-13140 (URN)978-91-88847-08-9 (ISBN)978-91-88847-07-2 (ISBN)
Presentation
2018-11-21, C120, Högskolan Väst, Trollhättan, 10:00 (engelsk)
Veileder
Tilgjengelig fra: 2018-11-21 Laget: 2018-11-19 Sist oppdatert: 2018-11-19
2. Electron beam-powder bed fusion of Alloy 718: Effect of process parameters on microstructure evolution
Åpne denne publikasjonen i ny fane eller vindu >>Electron beam-powder bed fusion of Alloy 718: Effect of process parameters on microstructure evolution
2020 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

Additive manufacturing (AM) is the technology of building 3D parts through layer-by-layer addition of material. Of the different types of AM techniques, electron beam-powder bed fusion (EB-PBF) has been used in this study. EB-PBF can build parts by melting metallic powders using an electron beam as the energy source. Compared to conventional manufacturing processes, EB-PBF offers a convenient approach and enhanced efficiency in producing customized and specific parts in the aerospace, space, automotive, and medical fields. In addition, the EB-PBF process is used to produce complex parts with less residual stress due to the high-temperature environment within the process.

This thesis has been divided into four stages. In the first stage, the behavior of Alloy 718 during the EB-PBF process as a function of different geometry-related parameters is examined by building single tracks adjacent to each other (track-by track) and single tracks on top of each other (single-wall samples). In this stage,the focus is on understanding the effect of successive thermal cycling on microstructural evolution. In the second stage, the effect of the position-related parameters–including the distance or gap between samples, height from the build plate (in the Z direction), and sample location on the build plate (in the X–Y plane) –on the microstructural characteristics, are revealed. These three position related parameters can have significant effects on the defect content and niobium rich phase fraction. In the third stage, the correlations between the main machinerelated parameters, geometric (melt pool width, track height, remelted depth, and contact angle), and microstructural (grain structure, niobium-rich phase fraction,and primary dendrite arm spacing) characteristics of a single track are delineated.

The results obtained in stages one to three were used as a guideline for the reduction of the internal–external defects and columnar-to-equiaxed transition(CET) in the grain structure of a typical cubic part. The final stage reveals two different strategies that were developed using machine-related parameters (scanning speed, beam current, focus offset, line offset, and line order number) to tailor the grain structures. All investigated parameters with respect to the proper selection of the processing window played a critical role in the solidification parameters (thermal gradient, growth rate, and cooling rate) on the solidification front, which could induce formation of more fine equiaxed grains.

sted, utgiver, år, opplag, sider
Trollhättan: University West, 2020. s. 75
Serie
PhD Thesis: University West ; 2020:37
Emneord
Additive manufacturing; Electron beam-powder bed fusion; Microstructure evolution; Microstructure tailoring; Process understanding; Alloy 718
HSV kategori
Forskningsprogram
Produktionsteknik
Identifikatorer
urn:nbn:se:hv:diva-16013 (URN)978-91-88847-65-2 (ISBN)978-91-88847-64-5 (ISBN)
Disputas
2020-12-01, F131, Trollhättan, 10:00 (engelsk)
Opponent
Veileder
Tilgjengelig fra: 2020-11-10 Laget: 2020-11-10 Sist oppdatert: 2020-11-10bibliografisk kontrollert

Open Access i DiVA

fulltext(2672 kB)388 nedlastinger
Filinformasjon
Fil FULLTEXT01.pdfFilstørrelse 2672 kBChecksum SHA-512
435248a86f7c65ff369a844f273950c65552ba3fc12df9be70a758312d50a99727649dce1f94bf9e1a8580749fca4f32f0e1b0bbfe0767209ac5c948693d0a46
Type fulltextMimetype application/pdf

Andre lenker

Forlagets fulltekstScopus

Person

Karimi Neghlani, PariaSadeghimeresht, EsmaeilAndersson, JoelNylen, Per

Søk i DiVA

Av forfatter/redaktør
Karimi Neghlani, PariaSadeghimeresht, EsmaeilAndersson, JoelNylen, Per
Av organisasjonen
I samme tidsskrift
The International Journal of Advanced Manufacturing Technology

Søk utenfor DiVA

GoogleGoogle Scholar
Totalt: 388 nedlastinger
Antall nedlastinger er summen av alle nedlastinger av alle fulltekster. Det kan for eksempel være tidligere versjoner som er ikke lenger tilgjengelige

doi
urn-nbn

Altmetric

doi
urn-nbn
Totalt: 221 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf