Enhanced sintering, microstructure evolution and mechanical properties of 316L stainless steel with MoSi 2 addition

Abstract

Sintering 316L stainless steel to near full density with an appropriate sintering additive can ensure high mechanical properties and corrosion resistance. We present here a sintering approach which exploits the dissociation of ceramics in steels at high temperatures to activate sintering densification to achieve near full dense 316L stainless steel materials. MoSi 2 ceramic powder was used as a sintering additive for pre-alloyed 316L stainless steel powder. Sintering behavior and microstructure evolution were investigated at various sintering temperatures and content of MoSi 2 as sintering additive. The results showed that the sintering densification was enhanced with temperature and MoSi 2 content. The distribution of MoSi 2 was characterized by XMAPs. It was found that MoSi 2 dissociated during sintering and Mo and Si segregated at the grain boundaries. Excess Mo and Si were appeared as separate phases in the microstructure. Above 98% of theoretical density was achieved when the specimens were sintered at 1300 °C for 60 min with 5 wt.% MoSi 2 content. The stainless steel sintered with 5 wt.% MoSi 2 exhibited very attractive mechanical properties.