Residual Lattice Strain and Phase Distribution in Ti-6Al-4V Produced by Electron Beam MeltingShow others and affiliations
2019 (English)In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 4, article id 667
Article in journal (Refereed) Published
Abstract [en]
Residual stress/strain and microstructure used in additively manufactured material are strongly dependent on process parameter combination. With the aim to better understand and correlate process parameters used in electron beam melting (EBM) of Ti-6Al-4V with resulting phase distributions and residual stress/strains, extensive experimental work has been performed. A large number of polycrystalline Ti-6Al-4V specimens were produced with different optimized EBM process parameter combinations. These specimens were post-sequentially studied by using high-energy X-ray and neutron diffraction. In addition, visible light microscopy, scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD) studies were performed and linked to the other findings. Results show that the influence of scan speed and offset focus on resulting residual strain in a fully dense sample was not significant. In contrast to some previous literature, a uniform α- and β-Ti phase distribution was found in all investigated specimens. Furthermore, no strong strain variations along the build direction with respect to the deposition were found. The magnitude of strain in α and β phase show some variations both in the build plane and along the build direction, which seemed to correlate with the size of the primary β grains. However, no relation was found between measured residual strains in α and β phase. Large primary β grains and texture appear to have a strong effect on X-ray based stress results with relatively small beam size, therefore it is suggested to use a large beam for representative bulk measurements and also to consider the prior β grain size in experimental planning, as well as for mathematical modelling.
Place, publisher, year, edition, pages
2019. Vol. 12, no 4, article id 667
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering
Identifiers
URN: urn:nbn:se:hv:diva-13611DOI: 10.3390/ma12040667ISI: 000460793300117PubMedID: 30813435Scopus ID: 2-s2.0-85062212588OAI: oai:DiVA.org:hv-13611DiVA, id: diva2:1292196
Funder
Luleå University of TechnologyEU, European Research Council
Note
Funders: InterReg ESS & MaxIV [MAH-003]; “Nationellt rymdtekniskt forskningsprogram” (NRFP); European Spallation Source–participation of the Czech Republic—OP”, [CZ.02.1.01/0.0/0.0/16 013/0001794]
2019-02-272019-02-272021-02-03