Deformation of a multiphase Mo-9.4Si-13.8B alloy at elevated temperatures

A 3-phase silicide alloy, Mo-9.4Si-13.8B (at.%), was prepared via powder metallurgy techniques. The tensile properties of the alloy at elevated temperatures were evaluated in vacuum at temperatures ranging from 1350 to 1550 °C and strain rates ranging from 5.0×10^-4 to 1×10^-3 s^-1. The alloy was found to exhibit a stress exponent of about 2.8 and relatively a high activation energy 740 kJ/mol. Also, it displayed unusually large tensile ductility (>100%) at T>1400 °C. The deformation mechanism as well as large ductility are discussed in the light of the microstructural observations. The alloy has a very good mechanical strength at elevated temperatures, comparable to some of the most advanced tungsten-based alloys.