Abstract: 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), (W_0.45Ta_0.5V_0.05)_0.9C_0.1, 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 (σ_YS-RT = 1409 MPa, ε_f = 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.

Key words: High-throughput alloy design, Refractory medium-entropy composite, High-temperature strength, Deformation mechanisms