Plunger Technique: A New Approach to Stir Casting AMMC Preparation

Abstract

Metal matrix composites (MMCs) are materials that are highly attractive for large range of hi-tech engineering applications. Keeping this in mind, materials for the present investigation were prepared by a drastically modified stir-casting technique where the usual solid shaft stirrer was replaced by a hollow/tubular spindle-stirring mechanism through which silicon carbide particulates in small cylindrical capsule were introduced to the aluminum-magnesium alloy matrix with the help of a plunger rod to obtain uniform distribution and low porosity in the product that are extremely important to this class of material. This plunger technique is a clear alternative to the established vortex route which is known to be the low-cost method amongst the lot. Interestingly, aluminum-magnesium alloy matrix material in this modified technique was also prepared similarly by directly introducing magnesium turning contained in mild-steel capsule plunger rod into Al-melt, which gives high Mg recovery (95%) in the alloy. It was found that modified stir-casting technique is simple to operate, smooth, trouble free, highly efficient and above all an inexpensive process in comparison to other methods.