Distinct Oxidation Behaviour Attributed to Phase Constitution Transformation at Different Hot Processing Temperatures in Fe-10Mn-5.5Al-0.25C Steel

Oxidation behaviour of Fe-10Mn-5.5Al-0.25C (wt.%) steel at 950-1150 degrees C has been investigated, which showed that oxidation resistance decreased largely with the elevated temperature. Phase constitution transformation included both the high-temperature austenite transformed into ferrite and into martensite. Phase constitution was modified by temperature which led to the transition of elements diffusing from the interface to volume diffusion, degrading the interface concentrations. The oxidation behaviour was changed from internal oxidation to homogeneous oxidation. The continuous and compact Al2O3 layers were more easily formed beneath inner oxide scales when oxidation at relatively low temperature and prevented further oxidation of the experimental steel.