Influence of GNPs@Cu on high-temperature mechanical and thermal properties of laminated MTZ composites

In this study, based on the design concept of nanocarbon-reinforced laminated metal matrix composites, the multiscale toughening effect of the natural laminated structure was applied to the fabrication of MoCu composites, and the laminated 60Mo35Cu2.5Ti2.5Zr composites (MTZ) reinforced with GNPs@Cu (copper-coated graphene) were prepared through the flake powder metallurgy process of ball milling and vacuum hot pressing. The results of microstructural characterisation and performance testing demonstrate that the unique two-dimensional structure of GNPs is highly geometrically compatible with the laminated structure, and the microstructural design of MTZ composites has been successfully realised. Additionally, GNPs can play the roles of fine grain strengthening and dislocation strengthening in the composites, and its regular arrangement in the microstructure can help to improve the load-transferring effect and thus further enhance the mechanical properties of the MTZ composites. Meanwhile, after the chemical plating treatment, the GNPs@Cu is well dispersed in the whole microstructure of the composites and is tightly bonded with the metal matrix, which effectively improves the interfacial bonding and reduces the interfacial thermal resistance as well as the hindrance to the movement of free electrons and phonons. Furthermore, the laminated structure can effectively take advantage of the high thermal conductivity of graphene in the plane direction to improve the thermal conductivity of MTZ composites in the plane direction.