Analysis of the evolution of the grain size distribution in WC–Co sintered materials with random set models

Coarsening of WC grains in equilibrium with a Co-based liquid is characterised by a gradual evolution of the mean grain size, while a population of large grains can form under certain conditions. Coarsening phenomena in such cases cannot be analysed simply in terms of average grain size. In this paper, grain size distribution is followed using a Boolean model. WC grains are represented by triangular prisms, with a log-normal grain size distribution. Model parameters are estimated from image analysis measurements. Variation of size distribution with sintering time is analysed. Accuracy of the method is discussed and its efficiency in characterising the abnormal character of grain growth is compared with more conventional measurements of intercept length distributions.