INVESTIGATION OF THE EFFECT OF INTERFACIAL CHARACTERISTICS ON THE MECHANICAL BEHAVIOR OF METAL MATRIX COMPOSITES

Abstract

Metal Matrix Composites (MMCs) reinforced with ceramic particulates are finding substantial applications in aerospace and automotive industries due to synergy of metallic properties such as ductility, toughness and environmental resistance with ceramic properties such as high strength and high modulus. MMCs are being used in engine applications, such as connecting rods and cylinder liners and as drive shafts and disc brake rotors. These applications require a fundamental understanding of thermal and mechanical properties of MMCs. MMCs are produced by adding ceramic particles in a metallic matrix. Hence a thin interface is formed between these two phases. The properties of this thin region play an important role in defining the mechanical properties of MMCs. The present research work aims at investigating the effect of interface properties on the mechanical behavior of MMCs with the, help of Finite Element Method (FEM). The effect of interface modulus, interface thickness and particle volume fraction on the effective elastic modulus and the flow behavior of the MMCs has been investigated. An attempt is made to further analyze the effect of interfacial characteristics on the stresses developed in the MMCs on applying combined thermal and mechanical loading. A unit cell model of MMCs is used for the Finite Element Analysis (FEA). The standard finite element software ANSYS is used for the modeling and analysis purpose. Firstly, the interphase is modeled as a single thin layer having uniform material properties through out the layer. The results obtained using this model matches qualitatively well with the results of other researchers obtained using in-house program. It has been reported that the metallurgical structure varies throughout the interface region. Therefore, subsequently the interface is modeled as four sub layers with properties varying from one sub layer to other. Different material properties are assigned to the sub-layers and the influence of variable interfacial characteristics on the effective elastic modulus of the MMCs is studied. The results obtained agree well qualitatively to those calculated using single interface layer model.