Exceptional strength-ductility balance and high softening resistance in TiZrNbV/Cu composites via gradient interfacial engineering

The refractory nature and high positive mixing enthalpies with Cu make TiZrNbV high-entropy alloy (HEA) particles promising candidates for enhancing the thermal stability of Cu matrix composites. In this study, the TiZrNbV/Cu matrix composites containing up to 25 wt% TiZrNbV were fabricated through a vacuum electrical current hot-pressed sintering process. The results showed that the gradient interdiffusion shells containing Cu solid solution, CuTi-rich and NbV-rich phases formed around the TiZrNbV reinforcement particles. The resulting composites demonstrated a remarkable strength-ductility synergy, along with excellent resistance to thermal softening. The 5 wt% TiZrNbV/Cu composite achieved a tensile strength of 305 MPa with 25 % elongation, 78 % IACS conductivity and high softening temperature of 800 °C. The formation of a gradient interdiffusion layer, rather than brittle intermetallics, is identified as the key to achieving strong interfacial bonding and high ductility, which highlights the potential of refractory HEA particles as next-generation reinforcements for high-performance metal matrix composites.