Microstructure Evolution of the Stainless Steel 316L Subjected to Different Routes of Equal Channel Angular Pressing

During the past decades, equal channel angular pressing has risen as a promising severe plastic deformation process and it is applied for the grain refinement and strengthening of metallic materials. Although the application of this process to improve the characteristics of austenitic stainless steels has been studied to some extent, little studies have considered the effect of route of the ECAP on this matter. This study aims to study the evolution of microstructure and the increase of hardness of stainless steel 316L during processing by two different routes of this process. For this purpose, the alloy is processed at the deformation temperature of 310 °C using two different routes of A and Bc. Afterwards, the microstructure evolution of the alloy is studied using the X-ray diffraction and the scanning electron microscopy. Results show that the applied ECAP procedure, irrespective of the applied route, causes a negligible occurrence of the phase transformation while it causes a widespread occurrence of twinning. This fact is related to the elevated temperature applied for the process. Also, the process causes a considerable increase in the hardness of the alloy mainly attributed to the occurrence of twinning.