Structure and properties of the diamond–WC–6Co composite doped by 1.5 wt % of CrSi2

Abstract

The influence of chromium and silicon on the structure of the diamond–WC–6Co composite doped by chromium disilicide has been studied at the meso-, micro-, and submicron levels. It is established that under the conditions of the structure formation of the diamond–WC–Co + CrSi₂ chromium and silicon do not dissolve in particles of diamond and WC carbide, they form a Co(W,C,Cr,Si) solid solution decreasing the energy of the stacking fault, which contributes to the Co_(fcc) → Co_(hcp) polymorphic transformation. Chromium interacts with atoms of carbon in diamond and WC carbide, as a result of which the graphite layer in the diamond/Co phase contact zone disappears and the Co₃W₃C carbide forms in the volume of the WC–Co-matrix. Chromium and silicon contribute to a good retention of diamond particles by the WC–Co-matrix and increase the ultimate strength in compression of the diamond–WC–Co+CrSi₂ composite.