Mechanical properties of diamond impregnated cobalt metal matrix

Abstract

Diamond Impregnated Metal Matrix (DIMM) composite materials are a class of materials used in cutting and drilling of stone and construction materials. This thesis examined the effects of diamond size and diamond concentration on various mechanical properties of Diamond Impregnated Cobalt Metal Matrix (DICoMM). The mechanical properties investigated were: fracture toughness, fatigue crack propagation, transverse rupture strength, absorbed impact energy (absorbed energy), hardness and erosive wear behaviour. A range of diamond sizes and diamond concentrations were used in the investigation. Due to the Powder Metallurgy (PM) manufacturing process percent theoretical density is an important factor which strongly affects the mechanical properties of PM type materials. The effects of percent theoretical density on the different mechanical properties were also investigated. The results reported and analysed show the various effects due to the addition of diamond to the cobalt metal matrix. From these results a number of predictive models were examined which yielded varying degrees of success. The Theory of Critical Distances (TCD) modelling was used to very good effect in predicting the transverse rupture strength of the DICoMM materials investigated in this thesis.