Effect of Microstructure, Morphology and Amount of Tungsten Carbides on the Properties of Laser Cladded MMC Coatings

Metal-matrix composite (MMC) coatings consisting of nickel based matrix, providing toughness, and tungsten carbides, providing wear resistance, are used in applications subjected to severe abrasive wear conditions. The aim of this work is to map the influence of microstructure, morphology and amount of tungsten carbides on the wear resistance and microstructure of laser clad MMC’s.

Abrasive wear, ASTM-G65, was mainly influenced by the volume fraction of the tungsten carbides in the coating. Shape and microstructure of the tungsten carbides had a minor impact on this property, for similar dilution and size of the tungsten carbides. Microstructure of the coating investigated by light and scanning electron microscopy showed that dissolution of the tungsten carbides in the melt and the phases formed at the interface carbide/metal matrix were influenced by the chemical composition of the liquid phase, the microstructure and the amount of tungsten carbides in the coating.