Mechanical Behavior of Al-SiCnp Nanocomposite Fabricated by Hot Extrusion Technique

Abstract

In this paper, fabrication and characterization of Al-SiC nanocomposites is investigated. The Al matrix is reinforced with different amounts of SiC nano-particles using mechanical milling, cold pressing, and, hot extrusion techniques. To get the best quality of the samples, the extrusion process is optimized firstly. With this regard, hot extrusion parameters such as the rate of extrusion, temperature, the extrusion ratio, lubrication, and the die set dimensions are experimentally studied. Finally, the nanocomposites with relative density more than 99% could be successfully fabricated under extrusion ratio of 8.5:1. As-extruded billets were then used to prepare standard tensile test specimens based on ASTM-E8. Afterwards, relative density, tensile behaviour, and micro-hardness of the samples were determined. The results show about 50% improvement for both the tensile strength and micro-hardness and near 1% reduction of relative density as the content of SiC reinforcement increases to 3 vol%. Therefore, specimens with higher strength-to-weight ratio which is a key parameter in aerospace and automotive applications can be produced using current techniques.