Work Hardening in a Fine Grained Austenitic Stainless Steel

Abstract

Grain size refinement in austenitic stainless steels to approximately 1 μm can be readily achieved with benefits to material performance. Reducing the scale of the microstructure in these materials, however, leads to complex changes in the strengthening behaviour owing to the presence of several deformation mechanisms. Understanding the interaction between grain size and mechanical response in these materials is thus central to identifying optimal material properties. In this study, we have examined the work hardening response of a stable austenitic stainless steel with grain sizes between 2 μm and 27 μm. The strongly grain size dependent work hardening behaviour at room temperature is shown to arise from both the grain size dependence of the dislocation storage as well as the grain size dependence of twinning.