Numerical homogenization and experimental study of the influence of graphite content and voids on the coefficients of thermal expansion of 2017 Aluminium matrix composites

Abstract

This paper investigated the use of Graphite in aluminum matrix in order to improve the durability for thermal management systems. Thus, the effective coefficient of thermal expansion (CTE), of aluminum matrix composites (AMC) with random spatial distributions of Graphite particles were studied with numerical samples. Using the finite element analysis, 3D thermo-elastic problems were solved with the application of different boundary conditions on a representative volume element (RVE) containing different volume fraction of spherical Graphite particles. A quasi-linear decrease of the CTE of the composites was observed as the Graphite volume fraction increases. The comparison of the numerical results of the CTE with theoretical ones showed a good agreement with the Schapery upper bound model. Due to the incompatibility of the CTE between matrix and particles, the addition of Graphite was prominent on the thermal stress of the composites. A sensitive effect of voids showed on thermo-elastic property. The obtained experimental results of CTE confirmed the trend depicted in the simulation results when the voids were incorporated.