Phase field modeling of crack nucleation and propagation in martensitic micro–structures

Abstract

In this paper, a combined phase-field (PF) approach has been considered to model fracture behavior under martensitic transformation effects. The effect of temperature as another degree of freedom has been studied, which has not been taken into account in previous studies. The concept of thermodynamic driving force, the elastic energy, interfacial energy, heat transfer and the kinetics of phase field equations are introduced to obtain the fracture domain, the martensitic evaluation, the temperature field and displacements [1]. Due to the high amount of stress at the crack tip, the martensitic transformation can start and propagate through the austenitic structure. The internal stresses between martensitic and austenitic layers deviate the crack path, leading to changes in the martensitic formation [2]. In addition, temperature plays an important role in this phenomenon in two aspects; first of all a change in temperature can produce thermal stress; and secondly, it affects the conditions for martensitic transformation. An increase in temperature requires more energy for the phase transformation [3], and changes in martensitic formation induce a new driving force for crack growth [2, 4].