Excellent strength-toughness synergy in metastable austenitic stainless steel due to gradient structure formation

Abstract

The effect of cold swaging and subsequent annealing on the structure and mechanical properties of a 321-type metastable austenitic stainless steel was studied. Cold swaging to a strain of 90% produced a gradient structure with a gradual decrease in the α-phase content from the edge to the center of the bar. Globular and lamellar regions of both strain-induced martensite and retained austenite were found in the center, meanwhile, a completely globular austenite-martensite dual-phase structure was formed at the edge