Fabrication and processing of aluminum alloy metal matrix composites

Abstract

ABSTRACT The present article demonstrates the procedure for fabrication of aluminum alloy 2014 based metal matrix composites having particulates of silicon carbide as reinforcement. Using the stir casting route, three different compositions of aluminum alloy metal matrix composites were fabricated. Microstructure of as-cast composites revealed a homogeneous distribution of silicon carbide particles along with few agglomeration and casting defects. Friction stir processing was performed to avoid such agglomeration and casting defects present in as-cast composites. The influence of friction stir processing parameters, that is, rotational speed and transverse speed on metallurgical properties, was investigated. Two combinations of rotational speed and transverse speed were considered: (i) 270 rpm and 78 mm/min and (ii) 190 rpm and 50 mm/min, respectively. As a result of friction stir processing, the microstructure of processed composites revealed the presence of fine silicon carbide particles along with the magnificent reduction in grain size. Composites processed with a rotational speed of 270 rpm and transverse speed of 78 mm/min were found to have higher grain refinement and as a result of this, the enhancement in microhardness was also observed. Except for a few cases, the average microhardness of all processed composites under both processed conditions was still lower than that of as–cast composites.