Particle-Reinforced Cu Matrix Composites by Direct Metal Laser Sintering (DMLS) Additive Manufacturing (AM): Interface Design, Material Optimization, and Process Control

Abstract

The interface design, material optimization, and process control during direct metal laser sintering (DMLS) additive manufacturing of (WC–Co)p/Cu composite parts were performed. By means of the addition of WC reinforcing particles in the form of WC–Co composite powder, the design strategy and formation mechanism of the graded interface during DMLS were investigated to improve the interfacial bonding and material integrity between the WC reinforcement and the Cu matrix. The effects of both laser processing parameters (e.g., laser power, scan speed, and powder layer thickness) and WC–Co reinforcement content on densification behavior, microstructural features (e.g., the particle dispersion homogeneity and the interfacial bonding ability), and mechanical properties (e.g., microhardness and its distribution, tensile strength, and fracture surface morphology) of DMLS-processed (WC–Co)/Cu composite parts were studied comprehensively, in order to propose the effective process control and material optimization methods to improve microstructural and mechanical performance of DMLS-processed metal matrix composites (MMCs). A detailed investigation of the influence of rare earth (RE) La2O3 addition on densification and microstructures of DMLS-processed (WC–Co)/Cu composite was performed, thereby proposing a key additive material for the improvement of the laser processing ability of MMCs.