|About this Abstract
|MS&T21: Materials Science & Technology
|Deformation-induced Phase Transformations
|Intrinsic Coupling between Deformation Twinning and Phase Transformation in NiTi Shape Memory Alloys and Metastable Beta Ti-alloys
|Yipeng Gao, Qianglong Liang, Yufeng Zheng, Dong Wang, Michael Mills, Hamish Fraser, Yunzhi Wang
|On-Site Speaker (Planned)
In addition to conventional dislocation plasticity, mechanical twinning and structural phase transformations are another two important plasticity carriers. In this presentation, we employ a combination of phase-transition-graph (PTG) analysis and TEM characterization to study systematically the deformation modes arising from the interplay between mechanical twinning and phase transformation. Using NiTi shape memory alloy and metastable beta Ti-alloy as examples, we show that mechanical twinning and phase transformations are intrinsically coupled in the symmetry-breaking processes, which results in multiple interconnected transformation and deformation pathways and characteristic twinning modes. This study not only reveals the physical origin of unique twinning modes and extended core structures of twin boundaries (e.g., nested twins) observed in experiments, but also provides new insights into the linear super-elasticity of cold-rolled NiTi and enhanced plasticity of metastable beta Ti-alloys through coupled twinning and transformation pathway coupling.