Anisotropic work hardening behaviour in duplex stainless steel under uni-axial loading: Interplay between phase morphology and crystallographic texture

Abstract

Duplex stainless steels (DSS) are characterised by vivid phase morphology and crystallographic textures. The typical microstructure consists of elongated phases (along rolling direction, RD) stacked alternatively along the normal direction (ND). In this study, uni-axial testing in multiple macroscopic directions is used to explore the anisotropic evolution of work hardening. Crystal plasticity simulations are used to gain insights into the same. The compressive stress and work hardening of samples loaded in the transverse direction (TD) are observed to be higher than those loaded in the RD and ND. Austenite and ferrite developed [110] and [111] parallel to the loading direction type fibre textures during uni-axial compression. The weak austenite texture behaves similarly to its single-phase counterparts regarding reorientation. The plastic anisotropy evolution is aided by the strong ferrite texture, which deviates from its single-phase behaviour. When loaded along TD compared to other directions, microstructural characterisation revealed the formation of deformation twins in austenite and lower effective slip length of both the phases.