An Experimental Study on the Role of Extrusion Ratio and the Resulting Soundness of Extrudate in Improving the Properties of Al-Cu/Sic Composites

Dhanalakshmi S, Sundaram KS and Ramesh CS

Published on: 2022-01-16


Aluminium matrix composites (AMCs) are the potential materials for many applications owing to their synergic properties. AMCs reinforced with coated ceramic particles show improved mechanical properties. In order to further improve the properties, the AMCs are subjected to secondary processing such as extrusion. In this study, aluminium matrix composites reinforced with Ni coated SiC particles, prepared by stir casting technique was subjected to plastic deformation through hot extrusion. Extrusion was carried out at three different extrusion ratios viz. 4:1, 8:1 and 10:1, at a constant billet temperature of 450 oC and a ram speed of 2 mm/s. Microstructure using OM, SEM, TEM and properties such as density, hardness, impact energy, flexural strength, tensile strength and compressive strength of the as cast and extruded composites were studied. Composite extruded at an extrusion ratio of 8:1 showed grain refinement, reduction of particle size and preferential alignment in the extrusion direction leading to increased hardness, density, impact energy and tensile ductility. While an extrusion ratio of 4:1 had resulted in the improvement of tensile strength, compressive strength and flexural strength of the composites. Composites extruded at 10:1 exhibited microstructural inhomogeneity resulting in inferior properties.