Synthesis of Aluminium Based Metal Matrix Composites (MMC) and Experimental Investigation of their Properties

Abstract

This thesis encompasses the work carried for the synthesis of aluminum based Metal Matrix Composite through powder metallurgy method and subsequent investigation of their properties. A composite material is a 'material system 'composed of a combination of two or more micro or macro constituents that differ in form, chemical composition and which are essentially insoluble in each other. Aluminum-matrix composites are not a single material but a family of materials whose stiffness, strength, density, thermal and electrical properties can be tailored. The matrix alloy, reinforcement material, volume and shape of the reinforcement, location of the reinforcement and fabrication method can all be varied to achieve required properties. The aim involved in synthesis of metal matrix composite materials is to combine the desirable attributes of metals and ceramics and subsequently investigation of mechanical properties of MMC which in turn can also be called Aluminum Metal Composite (AMC), as aluminum being the base matrix material.

The present work is based on synthesis of Aluminium based Metal Matrix Composite using ceramic particles. Silicon Carbide (SiC) and Aluminum Oxide (A2O3) both in powder form were selected as reinforcing elements. Silicon carbide was added in the matrix of aluminium from 5% to 25% in the step of 5% each time and subsequently Al-MMC was fabricated through powder metallurgy process. After preparing the MMC in form of cylindrical ingots density analysis, hardness measurement, evaluation of compressive strength and indirect tensile strength tests were carried out. Wear test was also done in order to evaluate the wear resistance. Microstructure of each types of composite having different weight proportions of SiC was also obtained.

Experimental results showed that 90\% of theoretical density was obtained, hardness of composite increases as weight proportions of reinforcing element increases from 5% to 25%. The same trend was also obtained in case of compressive strength. Wear test was also conducted and wear rate was evaluated and it was also found to be decreasing as content of SiC in Al- Matrix increases as expected.