SIMULATION OF VOID GROWTH IN WC-CO HARDMETALS USING CRYSTAL PLASTICITY THEORY

This paper describes an investigation of the deformation of the Co bin der in a WC-Co hardmetal, based on the simulation of void growth in th e microstructure. The growth of a periodic arrangement of voids is ana lysed over a range of macroscopic strain slates. The modelling involve s a detailed description of the microstructure incorporating a physica lly based, finite deformation, rate dependent, crystal theory of plast ic slip. The theory is implemented using the finite element method. Th e effects of void shape, overall stress state and binder layer thickne ss on void growth behaviour are assessed. Results are also presented s howing the effects of varying the lattice orientation as well as slip system arrangement. Comparison is made with the predictions of phenome nological constitutive theories, J(2) flow theory with isotropic harde ning and J(2)-based Gurson theory allowing for dilatant plasticity, an d the incompressible, isotropic power law analytical model of Duva con taining a dilute concentration of spherical voids, to assess the impor tance of detail in the material description. Copyright (C) 1996 Elsevi er Science Ltd.