Study on mechanical, electrical properties and interfacial bonding of high-strength graphene nanosheets (GNSs)/CuCrZr composites prepared via laser powder bed fusion

Abstract

The high optical reflectivity and thermal conductivity of copper make it challenging to form fully dense, high-strength, and high-conductivity copper alloy parts through laser-based additive manufacturing. In this paper, a new method for manufacturing high strength and conductivity copper alloy components by using optical absorption GNSs-coated copper powder and LPBF technology is proposed. The densification behavior, microstructure evolution, mechanical properties, and electrical and thermal conductivity of GNSs/CuCrZr composites prepared by laser powder bed fusion under different process parameters were studied. The high density of 99.58 % was obtained by optimizing the process parameters. With the increase of E_a, the grain size of the cross section is fine and uniform. The columnar grains in the longitudinal section are slender and grow epitaxially along the deposition direction. The yield strength, ultimate tensile strength, and total elongation at break are 220 MPa, 285 MPa, and 30 %, respectively. This is due to the generation of uniformly dispersed and fine precipitates and high-density dislocations. In addition, the interface characteristics and formation mechanism of GNSs/CuCrZr composites were also discussed by first-principles calculations and experimental studies. The interface between GNSs and CuCrZr is well-bonded, and there is a good agreement between the calculated and experimental data.