Production of Metal Matrix Composites Using Thixoinfiltration Techniques

Abstract

The work presents an innovative approach to produce metal matrix composites by using thixoforming techniques. The proposed procedure is based on the infiltration of thixotropic semisolid metal into an assembly of loose particles of reinforcing material. Experiments were performed using Al alloys as base metal and SiC and porous ceramic particles (expanded clay known as cinasite) as reinforcement. Process parameters are investigated to observe their influence in the quality of products. Results demonstrate that the process is flexible for the manufacturing of different distributions of reinforcing agents, such as homogeneous or layered composites. Moreover, it is also shown that metallic chips can be used as raw material, meaning an important possibility for materials recycling. It can be concluded that Thixoinfiltration is a simple and low cost technique to produce different types of MMCs, with advantages upon techniques involving metal powders, which usually require long milling and sintering periods. Thixoinfiltration can be also advantageous upon techniques involving liquid processing, once lower temperatures are involved and so lower energy input, as well as less interface reactions.