Kayser, W.; Bezold, A.; Chen, G.; Broeckmann, C.; van Kempen, S.; Boin, M.: Numerical Simulation of Residual Stresses in Hardmetals Using an Elastic-Viscoplastic Material Description. In: World PM2016 Proceedings, Powder Metallurgy World Congress 2016 Hamburg, 09.10.2016 - 13.10.2016. Hamburg: EPMA, 2016. - ISBN 978-1-899072-48-4
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Abstract:
Based on five mesoscopic 2,5D representative volume elements (RVE) representing a WC6wt.-%Co hard metal grade, the temperature dependent internal and final residual stress state is predicted by FEM using an elasto-viscoplastic modelling approach. The utilized models are semi automatically derived from backscatter electron micrographs and extruded in the third dimension get a more realistic deformation pattern compared to plane strain or plane stress assumptions. For the isotropic visco-plastic material description of the binder alloy (Co), Voce hardening law in combination with the Nor-ton-Bailey law is used for modelling the creep and relaxation behaviour. The mechanical behaviour of the carbides (WC) is assumed to be in the isotropic elastic region. The internal stresses are predicted in a temperature range between 900 °C and room temperature (RT). The temperature dependent in-ternal stresses are compared to neutron diffraction results for the same hard metal grade.