Application of the Extrusion to Increase the Binding between the Ceramic Particles and the Metal Matrix: Enhancement of Mechanical and Tribological Properties

Aluminum alloyed with magnesium and silicon has been used as the matrix material owing to its excellent mechanical properties coupled with good formability and its wide applications in industrial sector. An extrusion process was developed to consolidate Al 6061-SiCp composites from mixed powders. The results show that the composites were fully densified, with no sign of pores or oxide layers observable in the optical microscope. The SiC particles were distributed uniformly in the matrix. As compared with 6061 alloys, the composites demonstrated a smaller elongation, but exhibited a higher Young's modulus and a larger work hardening capacity. These composites possessed much higher elongation at the same strength level. The present study also addressed the dry wear behavior of the composites at different sliding speeds and applied loads. Values of the friction coefficient of the matrix alloy and composite materials were in expected range for light metals in dry sliding conditions. All of these improvements were attributed to the merits, including full densification of the bulk, uniform dispersion of the SiC particles in the matrix, and strong binding between the SiC particles and the matrix resulting from the extrusion.