About this Abstract |
Meeting |
2025 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2025)
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Symposium
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2025 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2025)
|
Presentation Title |
Laser Powder Bed Fusion of NiTi: Compositional Effect |
Author(s) |
Zhiheng Hu, Jingjing Yang, Asker Jarlöv, Duy Nghia Luu, Kun Zhou, Hang Li Seet, Sharon Mui Ling Nai |
On-Site Speaker (Planned) |
Duy Nghia Luu |
Abstract Scope |
Additively manufactured NiTi shape memory alloys (SMAs) face major challenges due to cracking and transformation temperatures sensitivity. This study investigates compositional effects in laser powder bed fusion (LPBF) using NiTi powders with 48-51.5 at.% Ni. Thermo-Calc simulations confirmed that increasing Ni content lowers the martensitic transformation temperature, consistent with experimental results. Using the same powder, higher energy density or shorter scanning vectors promote Ni evaporation, increasing Ti content and raising transformation temperatures. Higher energy density and shorter scanning vectors both intensify cracking. Thermo-Calc simulations further confirmed that changes in chemical composition affect the solidification cracking index, proven by the obtained process windows using different powders. Using equiatomic NiTi powder, proper LPBF process produced crack-free coupons with UTS over 800 MPa and elongation above 12%, without post-heat treatment. This study clarifies composition sensitivity in LPBF-processed NiTi SMAs and provides a data library with guidance for future control and design. |
Proceedings Inclusion? |
Planned: Post-meeting proceedings |