Modelling of Damage and Failure in Multi-Phase Microstructures through Phase Field Fracture

Multi-phase materials, such as fiber reinforced composites, metal matrix composites, or dual-phase steels, contain two or more contrasting phases within their microstructures. The coexistence of hard/brittle phases with soft/ductile phases leads to complex crack initiation and propagation behavior that influences the macroscopic performance of the material. The mechanical response of these materials is governed not only by the intrinsic properties of each phase but also by their spatial distribution, morphology, and volume fraction. This work presents a computational study aimed at understanding failure initiation and propagation in two-phase microstructures using a phase field fracture framework. A threshold based extension of the phase field model for ductile fracture is utilized. Furthermore, cohesive zone modelling is utilized to specifically simulate debonding of phases. Model performance is demonstrated on representative two phase microstructures.