Synergistic effect of grain size and second-phase particle on the oxidation behaviour of a high-manganese austenitic heat-resistant steel

The effect of grain size and second-phase particles on the oxidation behaviour of a high-manganese austenitic (HMA) heat-resistant steel are investigated. Four HMA steels with controlled grain size and volume fraction of second-phase particles are prepared and then exposed at 1023 K in air for 400 h. The results show that the particle-reinforced HMA heat-resistant steels exhibit excellent oxidation resistance. A physical model was proposed to investigate the synergistic effect of grain size and second-phase particle on the oxide scale evolution in HMA steels. The presence of second-phase particles can significantly reduce the effective grain size for the oxide scale formation by providing diffusion channels. Therefore, the formation of nodular oxide and the occurrence of internal oxidation are effectively inhibited in the particle-reinforced heat-resistant steels.