Structure-Property Correlations in Metal Matrix Composites

Metal matrix composites (MMCs) having particulate or laminate structure are extensively used in a wide range of applications including cutting tools, automotive vehicles, aircraft, and consumer electronics. In a composite material, two or more dissimilar materials are combined to form another material having superior properties. The matrix is a continuous phase in a composite material and is usually more ductile and less hard phase. In the matrix phase, aluminum, magnesium, titanium and copper are some of the metals widely used matrix materials. Compared with unreinforced metals, MMCs offer much better mechanical and thermal properties as well as the opportunity to tailor these properties for a particular application. In order to fabricate MMCs, various processing techniques have been evolved which can be categorized as liquid state method: Stir Casting, Infiltration, Gas Pressure Infiltration, Squeeze Casting Infiltration, Pressure Die Infiltration, solid state method: Diffusion bonding, Sintering and vapor state method: Electrolytic co-deposition, Spray co-deposition and Vapor co-deposition. The microstructure of MMCs such as orientation, distribution and aspect ratio of reinforced phase can effectively influence the properties of composite materials. The effective properties of MMCs can be predicted using the analytical or numerical methods. Analytical methods such as: Turner Model, Kerner Model, Schapery bonds, Hashin’s bond and Rule-of-Mixtures are used widely for effective properties computation. However, analytical methods cannot take into account the material microstructure, and therefore, the finite element method has been used extensively to model the real microstructure of composites and to predict the deformation response and effective properties of composites.

Keywords: Hashin bound, Metal matrix composites, Shtrikman bound, Structural properties.