A Micromechanics approach to evaluate the interface of metal matrix composites

Abstract

Metal matrix composites (MMCs) integrate the ductility of metal and the toughness of ceramic particles. The degree of alliance of metal and ceramics constituents can be quantified in terms of interfacial activity. Powder metallurgy processing employs lower temperatures and, therefore, reduced diffusion rates with better control of interface reaction kinetics. Powder metallurgy route gives way to three crucial steps: mixing, compaction followed by sintering. Mixing and sintering are two characteristic features which govern the final mechanical properties of the material. The distribution factor is influenced by mixing parameter and the strength factor is dominated by sintering parameter. The distribution factor commands the stress required to move a dislocation across two particles. The strength of the material dictates the performance of the material. The sintering of composites is an imperative issue in the material chemistry industry. The sintering of composites is driven by differential thermal activation and response of the matrix and reinforcement entities. The sintering of nanocomposites encompasses another issue that is the minimization of agglomeration of nanoparticles during blending. The sintering technique plays a vital role in deciding the matrix-reinforcement bonding. The interface is a frontier zone of the composite which idealizes in maximum bonding but minimum chemical reactions. The interaction, intermixing and interpenetration of nanoparticles into the matrix are the blue print of the mechanical index of the nanocomposites. The mechanical behavior of any material is dependent on the microstructure of the material. The introduction of reinforcement particles into a monolithic material alters the microstructure of the material and changes its mechanical properties. The supercritical applications of nanocomposites have led to an idea of ultra supercritical study of the interface. The critical study of the interface can be quantified by micromechanics approach. Micromechanics approach can involve only numerical modeling as well as microstructure evaluation followed by numerical simulation. The micromechanics approach here will be based on study of failure and fracture on the basis of micrographs followed by numerical simulation. Crack growth in particle reinforced composites is significantly influenced by the size, orientation, morphology and distribution of the reinforcement particles. The micromechanics approach to evaluate the interface of the metal matrix composite aims at understanding the interfacial failure by 3 point bending tests followed by fractography. Scanning Electron Microscopy along with the Atomic Force Microscopy are techniques to study the fracture surface of the nanocomposites. The micrographs give a precise idea about the crack initiation and propagation. The regions which are responsible for promoting as well as hindering the crack can be quantified by this technique. The micrographs are a prototype which can be numerically simulated to float a deformation theory of the metal matrix nanocomposites.