Machining Versus Heat Treatment in Additive Manufacturing of Ti6Al4V Alloy

Alireza Dareh Baghi, Shahrooz Nafisi, Reza Hashemi Oskouei, Heike Ebendorff-Heidepriem, Reza Ghomashchi

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

Abstract

Anisotropy in the mechanical properties of Laser Powder Bed Fusion (L-PBF)-fabricated titanium parts, which could be problematic in service, is dependent on the build directions and may be mitigated by post-fabrication treatments such as surface machining or heat treatment. However, investigation of the anisotropy in truly as-printed conditions, i.e., prior to any post-process, is always a challenge as the horizontally built parts are noticeably distorted compared to vertically built ones. In this study, by deploying a novel design, straight horizontal samples in the as-printed condition were fabricated. This allowed a comparison to be made possible in the mechanical properties of two built orientations of vertical and horizontal in the as-printed condition. This paper discusses how the surface machining or post-thermal treatment influences the anisotropy in the mechanical properties compared to as-printed conditions. It further highlights how annealing process at a temperature of 850 °C is more effective than stress relieving at a temperature of 670 °C to nearly diminish the anisotropy in mechanical properties even without any need for machining. Therefore, when machining becomes less feasible due to the geometrical complexity of L-PBF parts, a thermal treatment may be the solution for better service performance.
Original languageEnglish
Title of host publicationTMS 2022 151st Annual Meeting and Exhibition Supplemental Proceedings
Editors The Minerals, Metals & Materials Society
PublisherSpringer Link
Pages187–197
Number of pages11
ISBN (Electronic)978-3-030-92381-5
ISBN (Print)978-3-030-92380-8
DOIs
Publication statusPublished - 7 Feb 2022

Publication series

NameMinerals, Metals and Materials Series
ISSN (Print)2367-1181
ISSN (Electronic)2367-1696

Keywords

  • Laser powder bed fusion
  • Ti6Al4V
  • Build direction
  • Machining
  • Stress relieving
  • Annealing

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