| About this Abstract |
| Meeting |
2025 TMS Annual Meeting & Exhibition
|
| Symposium
|
Additive Manufacturing and Alloy Design: Bridging Fundamental Physical Metallurgy, Advanced Characterization Techniques, and Integrated Computational Materials Engineering for Advanced Materials
|
| Presentation Title |
Improving Tensile Strengths of Laser-Direct Energy Deposited (L-DED) NiTiHf Alloys by Printing Dislocation Structures |
| Author(s) |
Soumya Mohan, Aaron Stebner |
| On-Site Speaker (Planned) |
Soumya Mohan |
| Abstract Scope |
Additive manufacturing of NiTi shape memory alloys is challenging due to the as-printed builds not satisfying the ultimate tensile strength and ductility requirements for biomedical applications. We attempted to improve both the tensile strengths and ductility of Laser Directed Energy Deposited (LDED) NiTi alloys by introducing a ternary alloying element (Hf), that would actively segregate during AM solidification, and help print dislocation structures into the as-solidified microstructure. While Hf segregation was indeed observed at the solidification cell boundaries in the as-printed LDED microstructure, dislocation structures were not observed. Next, increasing dwell time between printed layers, switching from NiTi build plate to Mo in LDED prints, and printing using Laser powder bed fusion (LPBF) was done to increase the cooling rates. LDED prints showed matrix dislocations in Transmission Electron Microscopy (TEM), and LPBF prints revealed lesser Hf segregation. TEM of LPBF microstructures and mechanical testing of LDED builds will be done. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Additive Manufacturing, Characterization, Solidification |