Study of consolidation processes in sintering in the presence of a liquid phase

Abstract

1. By using the dilatometric method, we investigated the sintering of W-Cu and TiC-Ni systems in the presence of a liquid phase in dependence on the porosity, the amount of liquid phase, and the temperature. 2. In correspondence with theoretical considerations, two sintering stages were observed: the regrouping and the solution-precipitation processes. The shape of the shrinkage vs. time curve for these processes qualitatively agrees with theoretical data [4]. 3. For the copper-tungsten system, a sharp increase in the amount of shrinkage with an increase in temperature was observed, the probable cause of which was an increase in the wettability of tungsten in copper. 4. Complete consolidation of the W-Cu system was not achieved. A higher degree of consolidation in this system can be secured for a higher degree of initial porosity. The optimum temperature for producing W-Cu specimens with the greatest density lies in the 1300–1350° interval. 5. It was shown that, owing to the solution-precipitation mechanism, complete consolidation of the TiC-Ni system can be secured if the amount of liquid phase is not less than 20–25% by volume.