Experimental Investigation, Numerical Analysis and Validation of Empirical Models for Thermal Behavior of Al 6061-Sic-Graphite Hybrid Metal Matrix Composites

Abstract

Metal matrix composites have been regarded as one of the most principal classifications in composite materials. The thermal characterization of hybrid metal matrix composites has been increasingly important in a wide range of applications. The coefficient of thermal expansion and thermal conductivity are regarded as the most important properties of Metal Matrix Composites (MMCs) based on thermal behaviour. Since nearly all Metal Matrix Composites are used in various temperature ranges, measurement of Coefficient of Thermal Expansion (CTE) and thermal conductivity as a function of temperature is necessary in order to know the behaviour of the material. In this research paper, the evaluation of thermal expansivity and thermal conductivity have been accomplished for Al 6061, Silicon Carbide and Graphite hybrid metal matrix composites from room temperature to 300°C. Aluminium based composites reinforced with Silicon Carbide and Graphite particles have been prepared by stir casting technique. The thermal expansivity and thermal conductivity of hybrid composites with different percentage compositions of reinforcements has been investigated. The results have indicated that, the thermal expansivity of the different compositions of hybrid MMCs decreases by the addition of Graphite with Silicon Carbide and Al 6061. Few empirical models have been validated for the evaluation of thermal expansivity and thermal conductivity of composites. Using the experimental values namely modulus of elasticity, Poisson ratio and thermal expansivity, computational investigation has been carried out to evaluate the thermal parameters namely thermal displacement, thermal strain and thermal stress. The thermal conductivity of hybrid composites with different percentage compositions of reinforcements has been investigated using laser flash technique. The results have indicated that the thermal conductivity of the different compositions of hybrid metal matrix composites decreases by the addition of Graphite with Silicon Carbide and Al 6061. Using the experimental values viz., density, thermal conductivity, specific heat capacity and enthalpy at varying temperature ranges, computational investigation has been carried out to evaluate thermal gradient and thermal flux.