Evolution of the WC grain shape in WC-Co alloys during sintering: Cumulated effect of the Cr addition and of the C content

摘要

The evolution of the WC grain shape in Cr doped WC-Co alloys is studied at several stages of the sintering treatment. The common shape of WC is a prism based on a truncated triangle. The habit planes are two prismatic facets and the basal plane. In this work, the WC grain morphology is quantified using transmission electron microscopy at several temperatures. Two shape factors are used to measure the anisotropy between the two prismatic facets and between the prismatic and basal facets. The cumulated effect of the Cr addition and C content is studied. The Cr addition increases the anisotropy between prismatic facets in the W rich alloy. A significant increase of the elongation factor is recorded in the C rich alloy while the effect is more limited in the W rich alloy. The results are discussed as a function of the factors influencing the grain shape: grain growth and difference in energy between the facets.