Effect of Aluminum Nitride (AlN) Addition on Wear and Mechanical Properties of Al-Si Alloy Composites Fabricated by Stir Casting Process

Abstract

The effect of AlN addition in Al-Si alloy composites on the mechanical properties and dry wear behaviour were studied using pre-selected parameter conditions. In this work, high purity of AlN powders with different weight percentage of 5, 7 and 10 were used as reinforced materials for the composites. Morphology of the reinforced composite indicated that both silicon grains and inter-metallic compounds were surrounded by the AlN particles. The presence of AlN in the Al-Si alloy showed a significant improvement in tensile properties in which 7wt% of AlN addition increased up to 25% compared to those of without any reinforcements. Fracture morphologies with small dimples, tear ridges and necking features indicated that ductile fractures had occurred on the Al-Si composites. At 25N load, alloys with 5wt% of AlN exhibited high wear resistances whereas at 70N, alloys with 10wt% of AlN showed a great improvement in wear resistance. SEM investigation also revealed that the presence of wear was also marked with prominent grooves, craters and scoring marks. Overall, alloys with 7wt% AlN addition possessed great improvement in hardness, tensile and wear resistance properties.