Strength-plasticity synergy from ambient to high temperature via gradient-ordering in boride-reinforced WTaV medium-entropy alloy

Developing next-generation hypersonic vehicles necessitates structural materials capable of withstanding extreme thermal gradients. However, conventional alloys usually sacrifice room-temperature plasticity for breakthroughs in high-temperature strength. Here, we report a (WTaV)₉₀B₁₀ refractory medium-entropy alloy (RMEA) that overcomes this trade-off, showing decent plasticity of ~6% at ambient temperature, high yield strength of 650 MPa at 1873 K and 242 MPa at 2073 K, and excellent thermal stability up to ~0.7 T_m. The RMEA comprises a BCC metallic solid solution and a boride phase. Interfacial segregation of boron atoms generates gradient-ordering phase boundaries (GOPBs), enhancing stress transfer and plastic compatibility. Strong interfacial bonding of GOPBs and the inherent stability of the dual-phase structure further enable remarkable resistance to ultrahigh-temperature softening. At 2073 K, GOPBs evolve into fully coherent interfaces, ensuring exceptional thermal stability at ~0.7 T_m. This work demonstrates a gradient-ordering strategy for achieving strength-plasticity synergy from ambient to ultrahigh temperatures.