Mechanical Properties of Nano SiC-Reinforced Aluminum A356 with Sr Modifier Fabricated by Stir Casting Method

Abstract

A356-matrix composites are used in many areas such as transportation, automotive, and food industries because of its light weight, ductility, and the ability to improve its mechanical properties. One of the most often problem of making composites is relatively high amount of ceramic particles tends to segregate in the aluminum matrix. So, in order to overcome this problem, relatively little amount of ceramic particles are used. In this work, the casting was conducted via stir casting method by various additions of 0.05%, 0.10%, 0.15%, 0.20%, and 0.25% volume fraction nano silicon carbide (SiC). 0.046 wt% of strontium (Sr) and 2 wt% of magnesium (Mg) were also added into the A356 aluminum matrix. The results show that the composite reached an optimum UTS of 176.1 MPa and an elongation of 6.92% with the addition of 0.25 %vf nano SiC. The wear resistance and the hardness of the composite also increased as the nano SiC particle increased. The increase of mechanical properties of the composite was contributed by increasing of nano SiC and also supported by a thin layer formation of magnesium aluminate (MgAl2O4) surrounding the nano SiC particles. The addition of Sr caused the morphology of eutectic Si in the microstructure to become fine and fibrous.