A preliminary assessment of the properties of a chromium silicide alloy for aerospace applications

A preliminary assessment of the physical, mechanical and oxidation properties of a two-phase Cr3Si alloy macro-alloyed with Mo for potential aerospace applications is discussed. Detailed cyclic, isothermal and low temperature “pest” oxidation studies conducted between 773 and 1773 K revealed that the alloy has excellent oxidation properties due to the formation of dual protective oxides scales of Cr2O3 at low temperatures and SiO2 at high temperatures. The alloy also lasted at least 100 cycles at 1473 K under the action of a 0.3 mach combustion flame in burner rig tests. The compressive brittle-to-ductile transition temperature of the alloy is about 1500 K. The compressive creep strength of the as-cast alloy at 1500 K is as good or better than MoSi2 reinforced with either SiCp or SiCw, respectively, while those of the powder metallurgically processed alloys are comparable only to the unreinforced MoSi2. The room temperature fracture toughness of the alloy was determined to be 2.5 MPa m12.