Diffusion-induced phase strengthening and interfacial stabilization of Cu-TiZrNbTa composites by SPS adjustment

High-strength, high-conductivity (HSHC) materials find broad application in environments demanding both high stress tolerance and efficient power transmission, where a precise balance between strength and conductivity is critical. In this study, refractory high-entropy alloy (RHEA) with excellent strength and thermal stability-equiatomic TiZrNbTa is developed as novel reinforcement materials in Cu matrix. The nanocrystalline TiZrNbTa phase, synthesized through mechanical alloying, provides superior reinforcing effect in the Cu matrix compared to coarse-crystalline TiZrNbTa phase. Controlled elemental diffusion between the two phases, achieved by adjusting the sintering temperature, further optimizes the interfacial bonding, resulting in Cu-20 wt% TiZrNbTa composites with ultra-high strength (1081 ± 33 MPa) and excellent conductivity (41.5 ± 2.5% IACS). The finding broadens the application potential of nanocrystalline RHEA as stiffening phases, promoting their integration into the design of HSHC alloys.