Synthesis of Aluminium–Graphene Nanocomposite Sintered Using Spark Plasma Sintering

Abstract

Graphene (Gr) has attracted tremendous attention for the synthesis of lightweight structural nanocomposites due to its excellent properties such as high Young’s modulus (1 TPa), high fracture strength (~125 GPa) and extreme thermal conductivity (~5000 W/m/K). Fabrication of pure aluminium–graphene nanocomposite is conducted using a chemical synthesis route followed by consolidation using spark plasma sintering process. The pure aluminium powder was initially cryomilled to refine the grain structure. Subsequently, nanocomposites of Al-reduced graphene (Al-Gr) were synthesized using a chemical method employing different proportions (by volume fraction) of graphene oxide (GO) dispersed in pure aluminium powder. The synthesized powder was ball milled under optimized conditions followed by spark plasma sintering. The powder and sintered Al-Gr nanocomposites are characterized by X-ray diffraction, Raman spectroscopy, SEM and TEM microscopy. The mechanical behaviour is evaluated using the indentation hardness method. GO was found fully converted to reduced graphene during SPS. The increased proportion of reduced graphene in aluminium powder has suggested improved mechanical properties such as hardness after SPS. The structure–property correlation of synthesized Al-Gr nanocomposites is discussed with regard to the improvement in the mechanical behaviour.