Environment-assisted cracking of Fe-32% Mn-9% Al alloys in 3.5% sodium chloride solution

Abstract The stress corrosion cracking (SCC) behavior of four austenitic Fe-32% Mn-9% Al alloys containing ≈ 1 wt% carbon was studied. All of the four alloys were susceptible to SCC in room temperature and 160°C NaCl solution. SCC was enhanced by applying an anodic potential. The crack path was transgranular, and cleavage-like regions were observed on the fracture surface. The corrosion-assisted microcleavage model proposed for the transgranular SCC behavior of face-centered cubic (fcc) materials very likely was the operating SCC mechanism of the austenitic Fe-Mn-Al alloys. Adding 1.23% Mo or 1.27% Si to the austenitic Fe-32% Mn-9% Al alloys did not change the SCC mechanism and crack paths. Adding 1.27% Si made the alloys more susceptible to SCC, but no such effect was observed with the addition of 1.23% Mo. All four alloys studied were susceptible to hydrogen embrittlement (HE) in 3.5% NaCl solution at large cathodic applied potentials, and the crack paths were intergranular. The addition of Mo, Cr, or S...