Deposition of WC/Ni clad layers with a pulsed Nd:YAG laser

A series of experiments was performed to investigate the production of WC/Ni clad layers on H13 tool steel using a pulsed Nd:YAG laser and optical fibers. The effects of laser parameters, such as laser pulse energy and pulse frequency as well as material parameters such as powder composition and shape on the clad layer geometry and microstructure, were investigated. The microstructure of the clad layers was assessed by optical and scanning electron microscopy in conjunction with x-ray diffraction. The results indicate that up to 1 mm thick, fully dense clad layers can be formed in a single pass from WC/Ni powder containing up to 70% by weight pure WC with an average laser power of 440 W delivered through a 600 µm diam, step-index glass fiber. The results further show that the WC powder composition and shape can affect the structure and composition of the coating. The coatings produced with pure, angular, monocarbide exhibited the highest retained volume fraction of WC particles.