A two-step high-throughput design strategy of refractory medium-entropy composites with strength-plasticity synergy from room temperature to 2000 °C

The quest for refractory alloys capable of operating beyond 2000 °C faces critical bottlenecks in strength retention, ambient plasticity, and manufacturability. This study introduces a novel refractory medium-entropy composite (RMEC), (W0.45Ta0.5V0.05)0.9C0.1, designed through a high-throughput framework integrating thermodynamic simulation, high-temperature strength calculation, valence electron concentration optimization, and carbon-induced eutectic engineering. The alloy achieves good castability and mechanical performance, exhibiting a synergistic room-temperature strength-plasticity balance (σYS-RT= 1409 MPa, εf= 4.11 %) and unprecedented 2000 °C yield strength (625 MPa) under compression tests— surpassing state-of-the-art refractory alloys and composites by 182 %–286 %. Multiscale characterization revealed a hypoeutectic microstructure comprising BCC1 and M2C phases with semicoherent interfaces. At room temperature, the alloy's strength-plasticity balance arises from (i) the strong strengthening effect of M2C carbides and (ii) the eutectic BCC1 accommodating plasticity through activating dislocations of multiple slip systems. At 2000 °C, thermally activated BCC2 and FCC precipitate within M2C and BCC1 phases, respectively. These precipitates exhibit low lattice mismatch with the matrix and semicoherent interfaces, effectively pinning dislocations and suppressing dynamic recrystallization. The dual-phase precipitation system provides persistent strengthening through interface-dislocation interactions, enabling exceptionally high-temperature softening resistance. This work establishes a paradigm for accelerated discovery of extreme-temperature materials via integrated computational design and heterostructure engineering.