WC-Co-Ni3 Al composites were prepared from WC+ Ni3 Al prealloyed powder and balanced coarse WC and Co powders by conventional powder metallurgy technology.The effect of Ni3 Al content on the WC morphology in WC-Co-Ni3 Al composites was investigated using scanning electron microscope and transmission electron microscopy.The results show that, with the increase of Ni3Al content in WC-36 vol% (CoNi3 Al)composites,the WC grains become rounder and finer.The dependence of WC grain shape on the Ni3 Al content is attributed to the different solubility of W in binder.Consequentially, with increasing the sintering time, surfaces of WC grains are strongly micro-faceted and stepped.Similar WC grain growth behavior in WC -36 vol% (Co-Ni3 Al)composites as that in WC-Co cemented carbide is considered to be responsible for the appearance of the faceted WC shape in WC-Co-Ni3 Al alloy.