About this Abstract |
Meeting |
2020 TMS Annual Meeting & Exhibition
|
Symposium
|
Fatigue in Materials: Fundamentals, Multiscale Characterizations and Computational Modeling
|
Presentation Title |
Propositions for Functional Fatigue and Fatigue-crack Initiation in Shape Memory Alloys |
Author(s) |
Ahmedsameerkhan Mohammed, Huseyin Sehitoglu |
On-Site Speaker (Planned) |
Ahmedsameerkhan Mohammed |
Abstract Scope |
Shape Memory Alloys (SMAs) are unique materials that hold the potential to offer enhanced fatigue life in applications involving appreciable strain amplitudes. This is done by way of favoring reversible phase transformation over irreversible plastic slip accumulation. Yet, there are fatigue-induced slip irreversibilities associated with transformation, an emissary mechanism for which was proposed by the authors. The present study proposes to model the ramifications of slip emission on the diminishing recoverable strain and hysteresis under fatigue loading. An atomistic approach involving Molecular Statics (MS) and Density Functional Theory (DFT) was chosen. The Burgers’ vector magnitudes and fault energies associated with the emitted slip in relation to the twin-partial on the internal martensitic TB is shown to dictate this behavior. In addition, the implications of slip-emission, over multiple fatigue cycles, to dislocation pile-up and subsequent fatigue crack initiation at the austenite-martensite phase boundary is explored. |
Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |