Preparation and Microstructure of Ir-Zr-W Alloys by Powder Metallurgy Route

Iridium alloys doped with approximate 4 at% Zr and 0.3 at% W alloying elements were fabricated for ultra-high temperature applications by powder metallurgy route. The phase compositions and microstructures of the composite powders and the alloy were investigated. It was found that Ir3Zr phase could not form and no mechanical alloying phenomenon occurred when the composite powder of Ir-ZrH2-W was prepared by high-energy ball milling even for 24 h, but it could be completely transmitted to Ir3Zr phase after calcinating at 1300 °C. The average grain size of the alloy prepared by the powder metallurgy route was 4–5 μm, and Ir3Zr phase was generated in-situ in Ir-based alloy during sintering process.