A phase-field model for interactive evolution of phase transformation and cracking in superelastic shape memory ceramics

This work presents a modified phase-field model for accurate coupling of phase transformation and cracking in shape memory ceramics. The existing phase-field models underestimate the elastic response at the beginning of the mechanical response. We modified the chemical free energy to control the rate of phase transformation and consequently obtain a physical elastic response before initiation of phase transformation. First, the forward and reverse martensitic phase transformation in a superelastic single crystal 3 mol% yttria-stabilized tetragonal zirconia is studied. Then, the interaction between phase transformation and fracture under displacement -controlled loading condition is investigated. The model predicts a realistic mechanical response and the experimentally observed microstructure and crack deflection due to the phase transformation. In addition, the model captures the reverse phase transformation and the stress drop due to the crack propagation.