Interfacial diffusion and property regulation of CoCrFeNiMo high-entropy alloy particle-reinforced Cu matrix composites fabricated by fast hot pressed sintering

Cu matrix composites reinforced with CoCrFeNiMo HEA particles were synthesized by ball milling and fast hot pressed sintering. The role of HEA content in governing the microstructure, mechanical behavior, and tribological performance of the composites was systematically clarified. During sintering, an evident interfacial interdiffusion zone developed between HEA and Cu, confirming effective metallurgical bonding at the interface. All the composites exhibited high relative densities above 98.1%, confirming the excellent densification capability of the FHP process. With increasing HEA content, the hardness continuously increased, whereas the tensile strength increased first and then approached saturation; meanwhile, the elongation gradually decreased. Among the investigated compositions, the 15 wt% HEA/Cu composite achieved the most favorable strength–ductility combination, reaching a tensile strength of 424.7 MPa together with an elongation of 16.1%. Tribological tests performed at 20 N and 20 mm/s showed that both the friction coefficient and wear rate gradually declined as the HEA fraction increased. Meanwhile, the prevailing wear mode shifted from abrasive/adhesive wear at low HEA contents to oxidation-assisted delamination at higher HEA contents. These results indicate that the introduction of an appropriate amount of HEA particles is effective in improving the strength and wear resistance of Cu composites through interfacial diffusion bonding and second-phase strengthening.