Anomalous cyclic oxidation behaviour of an Fe-Mn-Si-Cr-Ni alloy - A finite element analysis

Abstract In previous research, an FeMnSiCrNi alloy presented anomalous behaviour during cyclic oxidation and gained mass after mass loss by spallation. Research clarified this phenomenon, but no stress analysis had been examined. This study investigates this anomalous behaviour using finite element analysis. FeMnSiCrNi alloy oxidation generates a Mn-depleted zone (ferrite) between the substrate (austenite) and oxide layer, and models containing austenite-ferrite-oxide demonstrated that increasing ferrite thickness and roughness (metal/oxide interface) decrease oxide layer stress, helping to comprehend why the alloy stops losing mass. The main cause, increasing roughness, was derived from ferrite plastic deformation and relates to austenite-ferrite thermal expansion mismatch.