Metal matrix composites for fabricating tooling

Abstract

The objective of this work is to investigate the fabrication, microstructures and, properties of metal matrix composites (MMCs) net-shaped using a four-step hybrid manufacturing method. The manufacturing method consisted of soft tooling fabrication, slurry casting, debinding-sintering followed by metal infiltration. Firstly, silicone rubber molds were fabricated. Subsequently, WC-Co pellets and stainless steel powders were mixed with polymer-based binders and cast into these rubber molds. After solidification, the parts were removed from the rubber molds, and placed in a furnace for debinding and sintering. Finally, sintered parts were infiltrated with bronze and the ensuing microstructures and properties were evaluated. The dimensional changes and mechanical properties of these MMCs as a function of amount of infiltrant were also examined. The results showed that the wear resistance of the MMC parts was comparable to M2 and D2 steels. Demonstrations of the process for net-shaping MMCs were conducted by fabricating wear-resistant tooling. The implications for fabricating MMCs by directly 3D printing rubber molds soft tooling are presented.