Load partition in NiTi shape memory alloy polycrystals investigated by in-situ neutron diffraction micromechanics modelling

摘要

Neutron diffraction experiments on NiTi polycrystals transforming in mechanical loads at constant temperature. The observed asymmetries between diffraction records of the martensite phase in tension and compression are interpreted as being due to the stress induced martensite texture caused by preferential martensite variant selection under stress. The evolution of the experimentally measured lattice strains and integral intensities of austenite and martensite reflections during compression pseudoelastic load cycle are interpreted with the help of the micromechanics model simulation of the NiTi polycrystal transformation. An information on the load partition mechanism in pseudoelastically transforming NiTi polycrystals is deduced.