Quantitative analysis of the effect of the binder phase composition on grain growth in WC-Co sintered materials

Microstructural evolution of WC-Co materials with different compositions and WC grain sizes is discussed from SEM observations and quantitative image analyses of intercept length distributions in the WC phase. Effect of the C/W ratio in the binder phase and of V- or Cr-dopants is particularly studied. Microstructural coarsening is shown to be more rapid and less abnormal when the C/W ratio is increased in the two-phase field {WC + liquid} and up to the three-phase field {WC + C + liquid}. The V-dopant does not completely suppress this effect. The composition dependence of the liquid stability-analysed from the calculated Gibbs energies of the phases-could explain the trend of the experimental results. (C) 2003 Kluwer Academic Publishers.