Simultaneously enhanced mechanical properties and electrical property of Cu-2 wt% Ag alloy matrix composites with analogy-bicontinuous structures constructed via in-situ synthesized graphene nanoplatelets

Abstract

Based on practical application requirements, the Cu alloy matrix with precipitates, particularly obstructing dislocation gliding, offers a promising pathway to substantially increase the strength of composites. Unfortunately, the fabrication of nano-precipitates often brings about extensive interface, which typically limits the electronic transmission capability and deteriorates the electrical conductivity. Herein, in-situ synthesized graphene nanoplatelets combined ball milling is deliberately selected to enable robust interfacial bonding and construct analogy-bicontinuous structures through hindering the diffusion of Ag in the Cu–Ag alloy matrix by the graphene nanoplatelets. The Cu alloy matrix composite after heat treatment exhibits a yield strength of ∼445 MPa and a fracture elongation of ∼13.5%, which is mainly ascribed to the introduction of the graphene nanoplatelets and the Ag nano-precipitates, and the adjustment of the analogy-bicontinuous structures. Meanwhile, the toughening mechanism of the Cu alloy matrix composite is rationalized on basis of delocalization and crack deflection affected by the graphene nanoplatelets and analogy-bicontinuous structures. Furthermore, the construction of continuous conductive path in the analogy-bicontinuous structures, refraining from the adverse effects caused by interface scattering, is of great benefit to the electrical conductivity, which is elevated to a high level of 92.2 IACS%. The present discoveries shed new insights into the innovative design of the Cu alloy matrix composites for advanced engineering applications by regulating the heterostructure.