| About this Abstract |
| Meeting |
2024 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advances in Titanium Technology
|
| Presentation Title |
Single-crystal Structure Formation of Ti–6Al–2Sn–4Zr–6Mo Alloy in Laser Powder Bed Fusion and Unique Alpha Variant Selection After Beta Annealing |
| Author(s) |
Tomonori Kitashima, Dennis Edgard Jodi, Takanobu Hiroto, Makoto Watanabe |
| On-Site Speaker (Planned) |
Tomonori Kitashima |
| Abstract Scope |
In the laser powder bed fusion (LPBF) using a flat-top laser beam, the process-parameter optimization leads to the planar melt pool geometry, thereby promoting the growth of solidification cells in the build direction. Herein, the single-crystal structure of Ti–6Al–2Sn–4Zr–6Mo (wt.%) was fabricated on the polycrystalline pure Ti substrate using the flat-top laser beam in LPBF. The cylindrical specimen was 12 mm in diameter and 30 mm in height. The as-fabricated microstructure exhibited ultrafine basket-weave with twelve alpha-variants. The short-time beta-annealing promoted the growth of <001>-oriented columnar beta-grains along the build direction with low-angle grain boundaries. The <001>-oriented beta-grains increased from the center outward with increasing height, forming a single crystal structure. The homogeneous near-<11-20> alpha-phase precipitated with minor <0001> alpha precipitations under the Burgers orientation relationship. Pole figures indicated the misorientation of these two alpha-variants is of the type [11-20]/60 degree, possibly owing to self-accommodation. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Additive Manufacturing, Titanium, Phase Transformations |