Article Fabricating a single-crystal-like β grain structure of a near-β Ti alloy with unique variant selection by laser powder bed fusion

Tomonori Kitashima SAMURAI ORCID (National Institute for Materials Science) ; Takanobu Hiroto SAMURAI ORCID (National Institute for Materials Science) ; Dennis Edgard Jodi ORCID (National Institute for Materials Science) ; Makoto Watanabe SAMURAI ORCID (National Institute for Materials Science)

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Citation
Tomonori Kitashima, Takanobu Hiroto, Dennis Edgard Jodi, Makoto Watanabe. Fabricating a single-crystal-like β grain structure of a near-β Ti alloy with unique variant selection by laser powder bed fusion. Materials & Design. 2024, 243 (), 113039. https://doi.org/10.1016/j.matdes.2024.113039
SAMURAI

Description:

(abstract)

A near-β Ti alloy with a highly anisotropic single-crystal-like β grain structure was fabricated on a polycrystalline pure-Ti substrate by laser powder bed fusion (LPBF) using a flat-top laser with bidirectional scanning and 90° hatch rotation. The as fabricated specimen had an acicular microstructure with 12 α variants. β-annealing followed by air-cooling revealed the growth of columnar β grains with a <001> orientation in the build direction from the center outward with increasing height, which formed a highly anisotropic β grain structure with a <001> orientation in the build direction and <100> or <010> orientation along the scan direction with low-angle grain boundaries (LAGBs) in the β matrix. The predominant <2-1-10>-oriented and minor <10-12>-oriented α phases precipitated from the <001>-oriented β matrix according to the Burgers orientation relationship. The <10-12>-oriented α phase was found to form on some LAGBs. Notably, a single α variant was widely distributed without forming multiple variant clusters across the highly anisotropic β grain structure.

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Keyword: Laser powder bed fusion, Titanium, Texture, Precipitation, Variant selection

Date published: 2024-05-23

Publisher: Elsevier BV

Journal:

  • Materials & Design (ISSN: 02641275) vol. 243 113039

Funding:

  • Amada Foundation AF-2022215-B3

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.1016/j.matdes.2024.113039

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Updated at: 2024-09-30 16:30:25 +0900

Published on MDR: 2024-09-30 16:30:25 +0900