Effect of hybrid ultrasonic-electromagnetic field on cracks and microstructure of Inconel 718/60%WC composites coating fabricated by laser cladding

In this study, a novel hybrid ultrasonic-electromagnetic (UEM) field was introduced into laser cladding (LC) to fabricate Inconel 718/60% tungsten carbide (WC) metal matrix composites (MMCs) coating on Inconel 718 substrate. Effects of hybrid UEM field on macrostructural, microstructure, phase composition, crack propagation and microhardness of MMCs coating were studied. Results show that under hybrid UEM field, the height of the MMCs coating increases, the cracks in MMCs coating can be effectively eliminated, the distribution of WC particles in the coating becomes more homogeneously, and the heat damage degree of WC particles is significantly decreased. Moreover, hybrid UEM field helps refine the microstructure and promote the transition of coarse carbide precipitates to the smaller spherical carbides. As a result, the microhardness of MMCs coating distributes more evenly in the coating under hybrid UEM field.