Enhanced sintering, microstructure evolution and mechanical properties of 316L stainless steel with MoSi2 addition

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. MoSi2 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 MoSi2 as sintering additive. The results showed that the sintering densification was enhanced with temperature and MoSi2 content. The distribution of MoSi2 was characterized by XMAPs. It was found that MoSi2 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.% MoSi2 content. The stainless steel sintered with 5 wt.% MoSi2 exhibited very attractive mechanical properties.

• Sintering behavior, microstructure evolution and mechanical properties of 316L stainless steel with MoSi2 addition were studied.
• MoSi2 dissociated into its constituents Mo and Si at the sintering temperature.
• A maximum sintered density of 98.2% of theoretical was achieved with 5 wt.% MoSi2 addition.
• Ultimate tensile strength 486 MPa and hardness 93 HRB were achieved for 316L stainless steel materials.