Tensile properties and strengthening mechanisms of Mo-Si alloy

Pure Mo and Mo-Si alloys with different silicon content were fabricated by powder-metallurgical and thermo-mechanical processing. Tensile properties of the pure Mo and Mo-Si alloys were measured at room temperature and the fracture surface was analyzed after test. The results indicate that Si can effectively reduced the grain size and improve the yield strength of Mo-Si alloys. With the decrease in grain size, the dominant fracture morphology is changed from intergranular to transgranular. The strengthening mechanisms were discussed and the yield strength was analyzed described with respect to grain size, solid solution hardening and Mo₃Si particle strengthening. Calculations show that the yield strength of Mo-Si alloys is governed by grain size.