Empirical quantitative relationships among grain size, mean free path, contiguity and cobalt content in WC-Co hardmetal

Abstract

Measured values of WC mean grain size, mean free path in cobalt and contiguity, have been plotted against each other and/or against the cobalt content for a set of WC-Co alloys having a wide range of grain sizes and cobalt contents. The relationships between these parameters are shown in graph form as well as by means of analytical expressions, allowing one to characterize fully the microstructure of an alloy of known composition by measuring only one parameter. This work has led to new insights into the microstructure of these alloys, e.g. have shown that with increasing cobalt content the contiguity of the carbide phase does not tend to zero, as previously assumed, but to a value of approximately 0.2, due to a tendency of the carbide grains to form clusters.