ICAMS / Interdisciplinary Centre for Advanced Materials Simulation


Effect of solubility and capillarity driven kinetics on sintered microstructure of WC-Co alloys

Date: 22.09.2017
Time: 12:00
Place: EUROMAT 2017, Thessaloniki, Greece

Raphael Schiedung
Marvin Tegeler
Fathollah Varnik

Liquid phase sintering involves a variety of physical processes, including capillarity, neck formation and coalescence, grain growth and coarsening, evaporation-condensation, as well as melting-solidification. The rate at which these processes proceed strongly depends on parameters such as temperature and pressure, grain size and on transport mechanisms such as surface, grain boundary and bulk diffusion, viscous flow and rigid body motion of individual grains. In the present work, we focus on the interplay between the dissolution of hard metal component in the liquid phase and the compaction kinetics. A finite solubility is beneficial for rapid compaction. It enhances the grain rearrangement dynamics under the action of capillary forces by dissolving the bonds which form in the early solid sintering stage, prior to the liquid donor melting. It is shown how the microstructure is influenced by the competition between dissolution kinetics on the one hand and the dynamics of grain rearrangements and compaction on the other hand. Moreover, the effect of the cooling rate and composition on these competing processes is also investigated.

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