A micromechanical model for the elastoplasticity and fracture of WC-Co hardmetals at large specimens scale

In this study a new constitutive model is developed for finite element modeling of tungsten carbide-cobalt (WCCo) hardmetals at large specimen level, called the microplane model for hardmetals. The model is first calibrated against the stress-strain test data under uniaxial tension and compression obtained from specimens with different grain sizes and cobalt contents. Then, with fixed calibrated model parameters, it is used to predict other experimental data obtained from uniaxial tension, uniaxial compression and four-point bending tests from the literature. It is shown to predict very well the experimental data on a wide range of cobalt weight fractions (from 3 to 27 wt%) and WC grain sizes (from 0.35to 1.85 mu m). The model needs as inputs only four commonly available material constants: the cobalt content, the grain size, the uniaxial compressive strength, and the uniaxial tensile strength.