A Phase-Field Study of Grain Boundary-Induced Martensitic Transformations in Bicrystals

Martensitic transformations (MTs) are solid-to-solid phase transformations where a parent phase called austenite (A) transforms into a product phase called martensite (M) which generally has multiple variants. The grain boundaries (GBs) are potential sites for the nucleation of martensite in polycrystalline solids which can undergo MTs, as observed in experiments and atomistic simulations (Ueland and Schuh in J Appl Phys 114, 2013;Ueda et al. in Acta Mater 49:3421–3432, 2001). A thermodynamically consistent finite strain-based multiphase-field model is presented here for studying MTs induced by GBs for cubic ↔ tetragonal transformations. The effect of an asymmetric planar tilt GB and the curvature of a GB are studied in bicrystals for the forward (A -> M) and reverse MTs (M -> A). The nucleation and growth of the martensitic microstructures are studied.