| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Phase Transformations and Microstructural Evolution
|
| Presentation Title |
Macroscopic Energy Barrier and Rate-independent Hysteresis in Martensitic Transformations |
| Author(s) |
Yongmei M. Jin, Yu U. Wang, Armen G. Khachaturyan |
| On-Site Speaker (Planned) |
Yongmei M. Jin |
| Abstract Scope |
A thermodynamic theory for the lower-bound hysteresis in martensitic transformations is presented. It shows that the elastic energy generated by the transformation-induced crystal lattice misfit produces a macroscopic barrier between the parent and product phases. Since this energy barrier is proportional to the macroscopic volume of the system and thus cannot be surmounted by thermally assisted nucleation of new phase, a rate-independent hysteresis of thermodynamic nature is produced, which sets the lower bound for the total transformation hysteresis. This lower-bound hysteresis is characterized by two critical temperatures of the martensitic and reverse transformations, where the necessary undercooling and overheating are intrinsic material properties determined by the lattice parameters of the phases. The theory is tested against experimental observations in representative Ni-Mn-Ga and Fe-Ni alloys, and their drastically different hysteresis behaviors are discussed. Phase field microelasticity simulation of hysteresis in a cubic-to-tetragonal martensitic transformation in polycrystal is also presented. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |