Effect of Nano-sized SiC Content on the Characteristics of Al-SiC Nano-composites Processed via Mechanical Milling

Aluminum matrix composites (AMCs) reinforced with silicon carbide particles have attracted considerableresearch interests due to their desirable mechanical properties such as high strength to weight ratio, low density andgood tribological properties. In this study, AMCs reinforced with different percentages of nano-sized silicon carbide(SiC) were fabricated by mechanical milling and powder metallurgy. Al 6061 powders in the size range of 38-63 μmwere co-milled with different percentages (1,2 or 3 vol.%) of nano SiC particles (25-50 nm) using high energymechanical milling to achieve Al-SiC nano-composite powders. After 20h milling, the SiC nano-particles wereembedded within the Al powders and the SiC nano-particles were distributed uniformly within the matrix alloy. Thesecomposite powders were cold pressed and hot extruded to produce Al/SiC composites. The porosity, hardness andshear strength of Al-SiC nano-composites were evaluated. The results confirmed that while the increased SiC contentresulted in increased porosity of green composites, the hardness and shear strength of hot extruded composites weresignificantly improved with SiC addition.

Keywords:

Aluminum matrix nano-composites , Mechanical milling , Porosity , Hardness , Shear strength