Meso-scale mechanical testing methods for diamond composite materials

Diamond composite materials prepared as thin layers on tungsten carbide substrates for applications such as rock cutting present characterisation challenges. As a consequence of the production route, the availability of only small pieces of diamond composite material has required some ingenuity in devising testing methods which are appropriate but which also yield accurate data to enable differences between grades of material to be characterised. A number of additional problems associated with their hardness and stiffness, coupled with difficulties of accurate machining, have to be overcome. This paper reports some of the techniques attempted to measure flexural strength, fracture toughness, elastic modulus, fatigue behaviour and edge chip resistance, and assesses their success.