Processing and microstructure of submicron WC–Co particulate reinforced Cu matrix composites prepared by direct laser sintering

In the present work, the submicron WC–10% Co particulate reinforced Cu matrix composites were prepared using direct metal laser sintering (DMLS). The phase, composition, and microstructure of the laser sintered samples were characterized. It shows that the WC reinforcing particulates are smoothened and refined, exhibiting compatible metallurgical interfaces with the matrix. The effects of processing parameters such as laser power, scan speed, and layer thickness on microstructures and properties of the laser sintered samples were investigated. It is found that below 700 W, increasing the laser power leads to a higher densification with an improved bonding ability between the reinforcement and the matrix. There exists a critical scan speed of 0.04 m/s which corresponds to the transition of pushing to trapping of particulates by the advancing solid/liquid interface, above which the distribution of particulates becomes more homogeneous with increasing the scan speed. A proper decrease in the powder layer thickness below 0.30 mm permits higher sintered densification and attendant mechanical properties.