Abrasive wear performance and microstructure of laser clad WC/Ni layers

Abstract

WC/Ni clad layers were produced on H13 tool steel substrates with a pulsed Nd:YAG laser and optical fibres using the injected powder technique. The effects of parameters, such as laser beam profile, WC powder shape and substrate pre-heat temperature on the clad layer microstructure and wear properties were investigated. The microhardness of the clad layers was measured using a Vickers microhardness tester. The microstructure of the clad layers was assessed by optical and scanning electron microscopy. The results show that up to 1 mm thick, fully dense and crack-free of WC/Ni clad layers can be formed on H13 substrates. The results further show that the higher is the microhardness of the clad layers, the higher is its wear resistance. Average surface microhardness values of the clad layers were as high as 650 HV. WC particle shape influences the microstructure and wear resistance of clad layer with crushed particles producing more wear resistant surfaces. The clad layers’ abrasive wear resistance was a factor of 5–10 times higher than that of unclad H13 tool steel.