|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Phase Transformations and Microstructural Evolution
||Role of Granular Constraint and Surface Effects on the Phase Transformation Mechanics in Shape Memory Alloys
||Harshad Paranjape, Partha Paul, Hemant Sharma, Jun-sang Park, Peter Kenesei, Catherine Brinson, Aaron P. Stebner
|On-Site Speaker (Planned)
Microstructural and structural constraint influences the superelastic performance of polycrystalline Shape Memory Alloy (SMA) applications in two ways. The interaction between austenite grain neighbors creates a complex stress state and potentially a less efficient martensite microstructure. Second the grains in the specimen interior vs. surface inherit a disparate strain state during any training/pre-deformation procedures applied. We combine in-situ measurements of deformation and microstructure using 3D X-ray diffraction (3DXRD) based experiments with microstructural, anisotropic elastic simulations to quantify the relative contributions of the two influences in a NiTi-based SMA. The simulations, informed by microstructural data from the 3DXRD experiments, provide rich information on the intragranular stress state, driving forces for martensitic transformation and theoretical transformation strains. These results are key to the development of processing paths and optimal microstructures for high performing SMAs and this approach demonstrates 3DXRD experiments as a tool to inform microstructural models of phase transformation.
||Planned: Supplemental Proceedings volume