Berlin 2018 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

MM: Fachverband Metall- und Materialphysik

MM 47: Poster Session II

MM 47.14: Poster

Mittwoch, 14. März 2018, 18:30–19:45, Poster C

Temperature dependence of interface energies in WC Co cemented carbides — •Erik Fransson, Martin Gren, and Göran Wahnström — Materials and Surface Theory, Chalmers University of Technology, Gothenburg, Sweden

Cemented carbides is a group of materials consisting of fine carbide phase (WC) particles cemented into a composite by a binder metal (Co). Cemented carbides combine superb hardness with high toughness making them ideal for usage in cutting applications and in wear resistance tools. Interfaces in cemented carbides play an important role in the sintering process of the material and for the resulting mechanical properties. Density Functional Theory has been used to calculate the driving force for spreading and binder phase infiltration of grain boundaries. However since sintering is carried out at 1800K, temperature effects are likely important. In this study we carry out a thorough investigation of temperature effects for interfaces in cemented carbides using an analytic bond order potential. We compute free energies using quasi-harmonic approximation and molecular dynamics simulations. Our calculation captures the vibrational and configurational entropy effects serves as a benchmark for free energy calculations methods for interfaces in general. The obtained temperature effects indicate that the spreading and infiltration parameters in cemented carbides increase with roughly 0.35J/m². This combined with previous DFT studies yield a picture consistent with recent spreading measurements and the fact that the material consists of a continuous carbide grain network.