Saturated solid-solution hardening behavior of Ir–Hf–Nb refractory superalloys for ultra-high temperature applications

The principles of multi-component alloying and saturated solid-solution hardening were combined for the design and development of Ir-based alloys for ultra-high temperature applications. It is found that as a solute, the transition metal Hf combined with Nb exerts its full potential for solid-solution hardening on the solvent Ir at room temperature and higher. With a monolithic saturated face-centered cubic structure, the Ir–3Hf–5Nb alloy has a 0.2% yield strength of as high as 140 MPa even at 1950 °C.