Rapid Achievement of High Frequency of CSL Boundaries in Austenitic Stainless Steel via Reduced Stacking Fault Energy

This study identifies a method for shortening the duration of annealing in the grain boundary control process to achieve a high frequency of CSL boundaries in austenitic stainless steel by focusing on decreasing stacking fault energy. Si-added SUSXM15J1, which has significantly lower stacking fault energy, was used to examine the impact of a decreased stacking fault energy on the duration of annealing after cold-rolling, necessary to introduce a high frequency of CSL boundaries, by comparing it with SUS304 austenitic stainless steel. It was found that a decrease in stacking fault energy significantly contributed to shortening annealing duration. The frequency of the CSL boundaries in SUSXM15J1 increased from 55% to 75% through 5% cold rolling and subsequent annealing at 1323 K for only 60 s. Ex-situ and in-situ EBSD observations revealed that the strain-induced grain boundary migration, accompanied by the formation of twin boundaries, likely occurred in SUSXM15J1 compared to SUS304, as the recovery process was hindered by the lower stacking fault energy resulting from Si addition.