Processing, Microstructure, and Properties of Multiphase Mo Silicide Alloys

摘要

Multiphase Mo silicide alloys containing T2 (Mo5SiB2), Mo3Si and Mo phases where prepared by both melting and casting and powder metallurgical (PM) processes. Glassy phases are observed in PM materials but not C materials. Microstructural studies indicate that the primary phase is Mo-rich solid solution in alloys containing <=(9.4Si+13.8B, at. %) and T2 in alloys with >=(9.8Si+14.6B). An eutectic composition is estimated to be close to Mo- 9.6Si-14.2B. The mechanical properties of multiphase silicide alloys were determined by hardness, tensile and bending tests at room temperature. The multiphase alloy MSB-18 (Mo-9.4Si-13.8B) possesses a flexure strength distinctly higher than that of MoSi2 and other Mo5Si3 silicide alloys containing no Mo particles. Also, MSB-18 is tougher than MoSi2 by a factor of 4.