High temperature oxidation resistance improvement in an FeMnSiCrNi alloy by Mn-depletion under vacuum annealing

Abstract FeMnSiCrNi alloys present good properties, although the oxidation resistance at high temperatures is limited by high manganese amount. Thus, the present study evaluated a vacuum annealing treatment on an Fe-17Mn-5Si-10Cr-4Ni-VC alloy as a surface modification method, aiming to improve oxidation resistance. The treatment was performed during 10 h at 1100 °C, generating an external ferrite layer of 170 μm in thickness (manganese decreased to 2 wt%). Oxidation tests at 800 °C up to 24 h in untreated and vacuum treatment demonstrated that heat treatment decreased the mass gain rate in two orders of magnitude through more protective oxide formation.