MICROSTRUCTURE AND THERMAL CONDUCTIVITY OF AL-GRAPHENE COMPOSITES FABRICATED BY POWDER METALLURGY AND HOT ROLLING TECHNIQUES

Abstract

The objective of this research is to improve the thermal conductivity and mechanical properties of Al/GNPs nanocomposites produced by classical powder metallurgy and hot rolling techniques. The microstructural evaluation confirms the uniform dispersion of GNPs at low content and agglomeration at higher contents of GNPs. The structure of graphene was studied before and after the mixing and the Raman spectra proofs that the wet mixing has a great potential to be used as a dispersion method. There is no significant peak corresponding to the Al4C3 formation in both the DSC curves and XRD patterns. The microstructural observation in both fabrication techniques shows grain refinement as a function of GNPs content. Moreover, it is revealed that the introduction of the GNPs not only improves the Vickers hardness of composite, but also decreases the density of the composites. The thermal conductivity investigations show that in both of press-sintered and hot-rolled samples, although the thermal conductivity of composites is improved at low GNPs content, but it was negatively affected at high GNPs content.