Abstract
In the previous work, we have derived a differential equation for the numerical calculation of the abnormal growth of WC grains in WC-VC-Co fine grained hardmetal, based on grain-dispersed alloy model with two kinds of grain sizes (2-grain-size model) where the rate-determining step of Ostwald ripening of WC grains is the interface reaction, and then numerically estimated the initial sizes of small and large grains where the abnormal grain growth occurs. In this work, first we derived differential equations for calculating each grain size and mean grain size in alloy model with three kinds of grain sizes (3-grain-size model), secondly calculated the large grain size and mean grain size after sintering for WC-0.5mass%VC-l0mass%Co fine grained hardmetal as a function of initial sizes of three kinds of grains and their initial mass fractions, and finally estimated both more detailed conditions for the occurrence or non-occurrence of the abnormal grain growth and the mean grain size.
