| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Fatigue in Materials: Fundamentals, Multiscale Characterizations and Computational Modeling
|
| Presentation Title |
G-13: A Microstructural Mechanism for Low-cycle Fatigue in NiTi Shape Memory Alloy |
| Author(s) |
Harshad Paranjape, Thomas W Duerig |
| On-Site Speaker (Planned) |
Harshad Paranjape |
| Abstract Scope |
NiTi shape memory alloy is widely used to manufacture implantable medical devices. Such devices typically undergo cyclic loading and are susceptible to fatigue failure. During cyclic loading, strain localization bands bounded by transformation fronts can form and reversibly propagate in NiTi specimens. Movement of transformation fronts leads to transformation-induced slip and consequently structural and functional fatigue. Thus, intuitively, larger transformation front movements should lead to larger transformation-induced slip accumulation and poorer fatigue lifetimes. In this work, we demonstrate that the fatigue lifetime of NiTi dogbone specimens in the low-cycle fatigue regime is indeed inversely proportional to the volume swept by the transformation front during a load-unload cycle. We elucidate the microstructural mechanism behind this phenomenon by decovoluting the role played by transformation-induced slip and micro-scale inclusions in causing fatigue failure. The understanding gained through this work will aid the development of a microstructural model for high-cycle fatigue in NiTi. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |