About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Dilute Alloying and Impurity Effects on Phase Transformations
|
| Presentation Title |
Dilute Compositional Modulation as a Design Lever for Martensitic Transformation in NiTi Shape Memory Alloys |
| Author(s) |
Zexu Chen, Hariharan Sriram, Longsheng Feng, Taiwu Yu, Jiaming Zhu, Jagannathan Rajagopalan, Yunzhi Wang |
| On-Site Speaker (Planned) |
Zexu Chen |
| Abstract Scope |
NiTi shape memory alloys exhibit superelasticity but suffer from sharp first-order B2-B19′ transformations that yield nonlinear stress–strain responses, long plateaus, and large hysteresis. This transformation is extraordinarily sensitive to Ni content: a shift of a few tenths of an atomic percent alters the local transformation temperature and, via the Clausius–Clapeyron relation, the critical stress. We exploit this sensitivity by treating dilute compositional variation as a deliberately engineered compositional modulation (CM) rather than an incidental impurity effect. Using phase-field simulations, we investigate how one-dimensional CM—defined by wavelength, amplitude, waveform, and mean composition—establishes a spatial spectrum of critical stresses governing transformation kinetics, microstructure, strain avalanches, and hysteresis. Specific CM parameters convert the sharp transformation into an apparently continuous transition, yielding low apparent modulus and reduced hysteresis. This work provides a predictive framework for designing high-performance CM-engineered NiTi via dilute composition control. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Computational Materials Science & Engineering, Mechanical Properties, Modeling and Simulation |