Numerical Analysis of Diamond Retention in Cobalt and a Copper-Base Alloy/ Analiza Numeryczna Retencji Kryształu Diamentu W Kobalcie I Stopie Miedzi

Why cobalt outperforms other matrix materials in its capacity for diamond retention in cutting tools is considered. To this end diamond loading conditions were modelled to establish the magnitude of stress and strain in the matrix surrounding a working diamond crystal. Only at 315 N did the contact force in Co result in plastic strain of 4-8%, which has a destructive influence on diamond retention. The strain field generated in a poorly performing Cu-40%Co-6%Sn matrix under a load of 190 N closely resembled that generated by 315 N in Co. It is postulated that diamond retention is related to the yield strength and work hardening characteristics of the metallic matrix.