A modified hardness model for WC–Co cemented carbides

Nanoindentation tests have been made to measure the elastic modulus and hardness of WC particles. Using a general relationship between elastic modulus, hardness, and representative stress of indentation, a constraint factor, i.e. hardness/yield stress, of 2.24 is determined for WC particles through nanoindentation test. With that as an input, finite-element simulations of indentations of WC–Co cemented carbides have been carried out and a constraint factor of 2.7 is obtained for WC–Co cemented carbides. Based on the so-determined constraint factors, a modification of Lee and Gurland hardness model is proposed. Comparisons of the modified hardness model and Lee and Gurland hardness model with the results of finite-element simulations and the experimental results from literature show that the modified model gives better estimation of the hardness of WC–Co cemented carbides.