FE-SIMULATION OF COMPACTION AND SOLID-STATE SINTERING OF CEMENTED CARBIDES

We have developed a tool for simulating the press cycle and the sinter ing cycle of cemented carbides. A constitutive model for compaction an d tensile fracture has been implemented in the explicit FE programme L S-DYNA2D, and it has been tuned to experiments of hydrostatic compress ion, uniaxial strain and conventional triaxial compression. The progra mme simulates the complete compaction cycle in a robust manner. Fricti on against the tooling is properly taken into account. We have further developed a constitutive model for the stress-free solid-state sinter ing to also account for a mechanical stress field. The sintering model is based on physical concepts, diffusion parameters, free surface ene rgy, dimensions of carbide grains, etc. of the constituents, and was t uned to successfully simulate the unloaded and loaded sintering of sim ple specimens. The models of compaction and sintering have a common se t of state variables, such that after the compaction cycle, and at rai sing the temperature the sintering starts out with proper account of t he residual stress field. Finally, the potential of the model is demon strated by simulating the production cycle of a simple WC-Co tool piec e until sintering to 75% of full density. The final geometrical shape of the specimen is compared to experimental data. (C) 1998 John Wiley & Sons, Ltd.