High strength, high ductility and high conductivity achieved in graphene nanosheets (GNSs)/copper alloy via laser powder bed fusion

Abstract

It is a great challenge for the laser-based additive manufacturing of complex copper (Cu) alloy components with high strength and high conductivity due to the low energy absorption rate from their high optical reflectivity and thermal conductivity. In this work, the additive manufacturing Cu alloy with high strength and flexibility, and excellent conductivity was fabricated by doping CuCrZr powder with GNSs. At a GNSs addition level of 0.075 wt%, elongation, tensile strength, and thermal and electrical conductivities of Cu alloy are improved by over 40 %. To reveal the enhancement mechanism of these physical and mechanical properties, both experiment and crystal plasticity modeling were applied to investigate the microstructure and deformation behaviors of these Cu alloys. It is found that the introduction of GNSs enhances laser absorption, thereby resulting in the nucleation and growth of large amounts of slender columnar grains that boost thermal and electrical conductivities. Moreover, the addition of GNSs also induces the formation of fine and dispersed precipitates with high-density dislocation tangles, thereby leading to improved alloy strength. Additionally, increased laser absorption also affects the texture components, which significantly enhances the ductility of Cu alloys. This study demonstrates a method to achieve Cu alloys with high performances by using laser-based additive manufacturing and can promote the application of additive manufacturing of copper alloys.