The effect of the geometry and properties of the diamond-carbide interface on the fracture strength of diamond-carbide blanks

A theoretical approach to the estimation of the effect of the diamond-carbide interface geometry and properties on residual technological stress and fracture strength of diamond-carbide blanks has been developed. A model has been suggested, which unlike those known in the literature, assumes the final strength of the working layer bonding with a substrate and adequately describes the nucleation and growth of an interfacial crack under the effect of residual stress and external load. The model parameters have been identified by comparison with the experimental data and the effect of thermobaric parameters of sintering on the level and distribution of residual stresses has been examined. In the mode of computing experiment the lowest required and the real adhesion strengths of the bonding of a diamond layer and a substrate have been defined. The use of the model allows solutions of the problems of designing diamondcarbide blanks with a minimum residual stress layer and a reasonable choice of the interfacial profile to increase the resistance to a brittle fracture.