Development of RuAl-based cast alloys

Heterophase RuAl-based alloys with a β-RuAl + (1–20) vol % ɛ-Ru structure and alloyed with chromium, titanium, and hafnium are produced by vacuum arc melting. The effect of the method of preparing charge materials on their behavior during alloy formation is studied. The effect of a structure on the deformability of the alloys at room temperature is estimated. All alloys exhibit ductility and can be deformed by upsetting at a strain higher than 10–12%. The effect of deformation by upsetting at 800°C and subsequent heat treatment on the structure and properties of the alloys is investigated. The high-temperature strengths of RuAl-, TiAl-, Ni₃Al-, and NiAl-based alloys are compared by measuring their hot hardnesses at temperatures up to 1100°C. The high-temperature strength characteristics of the RuAl-based alloys are higher than those of the Ni3Al-, TiAl-, and NiAl-based alloys over the entire temperature range under study; at temperatures ≥900°C, the hardness of ruthenium monoaluminide is higher than those of the other alloys by a factor of 2–4.