A thermodynamically-consistent non-isothermal phase-field model for probing evolution of crack propagation and phase transformation

Probing interactions between crack propagation (CP) and phase transformation (PT) under thermo-mechanical environment is an important challenge in accessing safety and reliability of advanced materials. These processes of CP, PT, thermal conduction, and stress evolution are intimately coupled in ways that collectively govern crack growth and phase transformation, but the coupling effect has not been comprehensively elucidated. Here we developed a thermodynamically-consistent non-isothermal phase-field fracture model coupled with PT. The model is able to capture the effects of kinetic and thermodynamic parameters on the spatiotemporal evolution of the CP and PT. Our numerical results show that under thermal-mechanical loading nucleation and growth of asymmetric PT near the crack tip can promote crack deflection, and furthermore heterogeneous PT in polycrystalline structure can aggravate crack nucleation and growth. These findings reveal that the intricate coupling of CP, PT, thermal, and mechanical effects provides non-neglectable contribution to thermal crack damage in advanced materials besides the contribution of thermal stress.