Silicide composite with niobium-based metallic phase and silicon- modified Laves-type phase

摘要

A silicide-based composite toughened with a niobium-based metallic phase and further containing a silicon-modified chromium-based Laves- type phase to promote oxidation resistance. The silicide-based composite generally contains one or more silicide intermetallic phases, each of which is an M.sub.5 Si.sub.3 -type or an M.sub.3 Si-type phase where M is at least Nb+Ti+Hf. The niobium-based metallic phase contains at least niobium, titanium, hafnium, chromium, aluminum and silicon. The silicon- modified Laves-type phase is of the Cr.sub.2 M type where M is Nb+Ti+Hf. The silicide-based composite is formulated to contain greater than 25 volume percent of the niobium-based metallic phase, the balance being the silicide intermetallic phases and the silicon-modified Laves- type phase.