Intrinsic Micromechanism of Multi-step Structural Transformation in MnNi Shape Memory Alloys

摘要

Simulation of the multi-step transformation of cubic matrix -> multi-variant tetragonal domain -> orthorhombic domain was realized by phase-field method. The intrinsic micromechanism of the second-step transformation in MnNi alloys was studied. It was found that the orthorhombic variant originated from the tetragonal variant with similar orientation, and bar-shaped orthorhombic phase firstly occurred around the interface of twinning bands. The second-step transformation resulted in localized variation of internal stress. (C) The Minerals, Metals & Materials Society and ASM International 2017