Tensile deformation of 316L austenitic stainless steel using in-situ electron backscatter diffraction and crystal plasticity simulations

In-situ electron backscatter diffraction of low stacking fault energy 316L austenitic stainless steel was carried out in tension to study the evolution of microstructure and micro-texture as a function of strain till fracture. The microstructure was characterized by extensive twinning throughout the deformation process. At low and intermediate strain, scattered areas of twinned regions are observed in the microstructure with <101> grains with higher Schmid factor showing extensive twinning. However, not all the grains with <101> orientation show twinning despite the higher Schmid factor during initial stages of deformation. However, the entire microstructure appeared uniformly twinned irrespective of the orientation of the parent grains near the fractured region. Twinning was also accompanied with evolution of intragranular misorientation and concomitant roughness evolution in the deformed state. It was observed that the grains with <100> orientation show higher roughness evolution and contribute to failure. Crystal plasticity simulations indicate that saturation in twinning leads to lower work hardening rate, ultimately leading to failure.