Core-rim microstructure and properties of WC/Ni composites

WC/Ni55 composites were prepared by vacuum sintering. The dissolution of WC in Ni55 was analyzed by SEM and XRD, and the effect of WC dissolution on the microstructure and micro-hardness of the composites was researched. The results show that the edge of the WC particles in WC/Ni55 composites dissolves partially, and a core-rim structure of the WC particles was formed. A metallurgical interface with good bonding was formed between WC particles and the matrix. The stable size of rim has no obvious correspondence with the original size of WC particles. M6C and other hard phases were precipitated at the interface, which significantly improved the micro-hardness of the matrix. The new precipitate also improved the scratch resistance of the composites in some case.