Investigation of the effect of inert inclusions on densification during solid-state sintering of metal matrix composites

摘要

Solid-state sintering is the most used process to produce composites. In this paper, the effect of inert inclusions on densification during sintering was evaluated for Cu-WC and Cu-W composites, which have several industrial applications. Dilatometry tests were performed to follow the densification of composites. The effects of the quantity, size, and interphase bonding on densification of the matrix were studied. Distribution of the inert particles inside of the matrix was observed by scanning electronic microscopy. The results show that densification is decreased as the volume fraction of inclusions increases. Two different behaviors are detected when two different sizes of inclusions are used. For &20% vol. of inclusions, smaller tungsten particles have a minor effect on the densification than those of tungsten carbide. On the contrary, higher volume fractions of smaller tungsten particles drastically decrease the densification. The microhardness of the copper matrix is improved up to 15% vol. of inclusions, being higher for tungsten carbide particles. It was found that 15% vol. of inclusions is the maximal quantity of inclusions that can be used, as higher quantities inhibit densification and reduce the mechanical properties of the composite.