Al Matrix Hybrid Composites Reinforced by Graphene Nano Plates and Nano TiC

Al matrix composites due to their lightweight, good strength, corrosion resistance and acceptable wearing properties attracted a number of industrial applications. In the present paper, Al matrix hybrid composites reinforced by Graphene nano-platelets and nano-TiC particles synthesized via mechanical milling followed by powder metallurgy method and the effect of these reinforcements addition on their microstructure, porosity and hardness investigated. Commercially pure semi spherical aluminum powders (<64 μm), nano TiC particles (40-60 nm) and Graphene nano-platelets (average platelets thickness < 1 μm) were used as the starting materials. The required amounts of Al and reinforcing particles were mixed and subjected to 6h mechanical milling, cold pressing and sintering at 600°C for 1 hour. SEM studies confirmed uniform distribution of reinforcements within the Al matrix. The porosity of Al-1vol.%Graphene-1vol.%TiC composite was higher than both the reference sample and Al-2vol%Graphene-2vol%TiC composite. However, Al-2vol.%Graphene-2vol.%TiC composite exhibited higher hardness than the reference sample and the other aforementioned composite. These results attributed to the role of TiC nano particles and porosity content in respectively increasing and decreasing the hardness of samples. Meanwhile, Graphene as a lubricant contributed in lowering porosity during cold pressing.