High-temperature mechanical properties and oxidation behavior of Hf-27Ta and Hf-21Ta-21X (X is Nb, Mo or W) alloys

The microstructure, mechanical properties (at 25 °C, 1000 1200 1400 °C and 1600 °C) oxidation behavior of a binary Hf-27%Ta alloy three ternary alloys, Hf-21%Mo-21%Ta, Hf-21%Nb-21%Ta Hf-21%Ta-21%W (compositions are in atomic percent) reported. alloys were produced by vacuum arc melting, hot isostatically pressed under high-purity argon pressure 207 MPa at for 3 h slow cooled to room temperature. Hf-27Ta had microstructure consisting coarse primary HCP particles monotectoidally transformed matrix nano-lamellar mixture the Ta-rich BCC Hf-rich phases. Hf-21Mo-21Ta consisted phase precipitates. Hf-21Nb-21Ta phase, spherical nano-precipitates inside grains two-phase lamellar regions grain boundaries, with no detected. Hf-21Ta-21W three-phase structure matrix, W-rich cubic Laves nano-lamellae limited ductility temperature but they all well workable T ≥ °C. Among studied was strongest high temperatures. kinetics Hf-27Ta, Hf-21 W-21Ta similar, 30–40 mg/cm2 mass gain per 1 holding exhibited much higher (~230 mg/cm2/h) gains showed evidence formation gaseous and/or liquid species oxide scales.