Mesoscopical finite element simulation of fatigue crack propagation in WC/Co-hardmetal

WC/Co is an important technical material used in a wide range of industrial applications such as cutting tools, drilling bits and drawing dies due to its excellent combination of wear resistance, strength and toughness. The focus of this study is the numerical study of the microscale fatigue crack propagation in WC/Co. In this respect, a damage model based on a continuum damage mechanics (CDM) approach was implemented in the commercial FEM solver Abaqus/Explicit for simulating the crack propagation in the material. Separate damage laws based on brittle failure and accumulated plasticity driven fatigue are implemented for the WC and the Co phases, respectively. The material parameters for the carbides are taken from literature. On the other hand, to obtain the material parameters for the binder, a particular model alloy has been developed representing the composition of the binder. Experimental tests carried out with this binder alloy have been used to identify parameters for the appropriate plasticity and damage models. In order to evaluate the performance of the approach, a numerical model based on an experimental case was generated. The numerical model reflected strong agreement in comparison with the real crack pattern generated during the experiment. Moreover, results of this study indicate a strong dependence of the fatigue crack propagation on accumulated plasticity within the binder phase; this effect suggests a novel understanding of the fatigue mechanism of this material and provides a basis for microstructural simulation. © 2014 Elsevier Ltd.