Wear performance of Ni-WC composites and heat-damage behaviour of WC particle during vacuum-induction melting process

Abstract

Ni-WC composites were prepared by vacuum-induction melting (VIM). A ball-on-disc wear test was performed using an Si3N4 ball as a friction pair to study the wear performance of the composites. The effects of WC particle size (average particle size of 68 μm and 23 μm) on the mechanical properties of the composites and the heat-damage behaviour of WC particles during the melting process were investigated. The results indicate that the wear rate of Ni-WC composites with coarse WC particles was lower than that of Ni-WC composites with fine WC particles. The predominant wear mechanism of composites with coarse WC particles was mechanical wear of the WC particles; the predominant wear mechanisms of composites with fine WC particles were oxidation wear and three-body abrasive wear. The coarse WC particles provide better wear resistance than fine WC particles. The WC particles underwent heat erosion and dissolution caused by the Ni-based melt. Increasing the size of the WC particles can significantly reduce the degree of heat damage to the WC particles and improve the hardness of the composites.