Finite element micromechanical modeling of elastic and thermoelastic constants in graphene nanoplatelet-aluminum nanocomposites

A numerical micromechanics approach based on the finite element method (FEM) is employed to evaluate the elastic modulus and coefficient of thermal expansion (CTE) of graphene nanoplatelet (GNP)-reinforced aluminum (Al) matrix nanocomposites. The modeling framework integrates representative volume elements (RVEs) with detailed consideration of GNP morphology in the nanocomposite structure. The critical role of GNP waviness and the formation of aluminum carbide (Al ₄ C ₃ ) interphase, resulting from the interaction between graphene and the metal matrix, is examined in relation to nanocomposite properties. Variations in the volume fraction, geometry, and alignment of GNPs, along with the interphase thickness and its material properties, are considered to capture the microstructural influence on the elastic modulus and CTE of GNP/Al nanocomposites. The study reveals that the presence and growth of the Al ₄ C ₃ interphase contribute positively to the mechanical and thermal elastic response of the nanocomposite. Although increasing graphene content, aspect ratio, and alignment enhances the elastic modulus and reduces the CTE, the presence of waviness in graphene nanofillers diminishes these benefits. Model validation is carried out through a comparison between micromechanics-based FEM outcomes and experimental data documented in the literature.