Shearable carbide reinforced refractory medium-entropy alloy with enhanced high-temperature strength and room-temperature compressive plasticity

Ultra-high-temperature components in hypersonic vehicles, aerospace propulsion, and nuclear energy systems demand structural materials that provide high strength above 1400°C while retaining sufficient room-temperature deformability. Conventional Ni-based superalloys cannot meet such temperature requirements, whereas refractory high-entropy alloys such as NbMoTaW offer superior high-temperature strength but are severely brittle at ambient conditions. Here, a Re_0.1Hf_0.25Ta_1.85W_0.2C_0.25 refractory medium-entropy alloy was designed and fabricated by vacuum arc melting, forming a carbide-reinforced multiphase architecture composed of a three-dimensional hexagonal close-packed M₂C carbide skeleton, a body-centered cubic metallic matrix, and shearable face-centered cubic MC plate-like precipitates. The continuous M₂C skeleton provides load-bearing capacity and resistance to high-temperature softening. Meanwhile, the (Hf,Ta)C precipitates deform by slip accompanied by dense stacking faults, which mitigates stress concentrations and inhibits premature cracking. Consequently, the Re_0.1Hf_0.25Ta_1.85W_0.2C_0.25 alloy exhibits an excellent compressive strength–plasticity synergy from room temperature to high temperature, with a true yield strength of 760 MPa and a true compressive strength of 910 MPa at 1450°C, together with a room-temperature true compressive fracture strain of 19.6%. This work provides an effective microstructural design strategy for carbide-strengthened refractory alloys with balanced high-temperature strength and room-temperature compressive plasticity.