Shape retention of cemented carbide prepared by Co melt infiltration into un-sintered WC green parts made via BJ3DP

Abstract

Direct melt infiltration does not produce sintered closed holes and considerably reduces the time required for preparation compared with pre-sintered WC skeleton followed by melt infiltration of Co. However, it may lead to alloy collapsing and deformation. In this study, WC and Co green parts were prepared via binder jet 3D printing. The two parts were stacked layer by layer then subjected to melt infiltration to prepare a WC–Co series of cemented carbides. The aim was to investigate the shape retention, infiltration conditions, and properties of the alloy after the equal distribution of Co and the direct infiltration of the Co melt into the WC green parts without pre-sintering. The effect of different Co amounts on the product was also studied. Results showed that the carbide prepared through direct melt infiltration of WC green parts without pre-sintered skeletons displayed excellent shrinkage and properties. The shrinkage of the prepared cemented carbide with a Co content of about 25 wt% was within 3% in all directions. The relative density, hardness, and fracture toughness of the alloy reached 96.65%, 11.5 GPa, and 23.5 Mpa m1/2, respectively. This work provides a simplified, and high-shape-retention method for other alloys that can be prepared through melt infiltration.