In this research, Graphene nanoplatelets (GNP) reinforced epoxy nano composites were fabricated via magnetic stirrer and ultra sonification assisted hand layup method. The impact of different weight percentage of GNP (0, 0.25, 0.50, and 1.0%) on different characteristics of nano composites was evaluated. The microstructure analysis of developed nano composite was determined by Field emission scanning electron microscopy. It was examined that epoxy nano composites containing 0.5 wt.% GNP have the highest tensile, flexural, and impact strength compared to neat epoxy. The reduction in tensile and flexural strength is achieved at 1% of GNP. Adding more nanofiller to a certain limit causes non-uniform dispersion and agglomeration of nanoparticles, which results in a reduction in properties. The 1% GNP reinforced nano composite has the highest value of shore hardness.

In this research, AA7068/Si3N4 composites were fabricated through stir casting with the attachment of ultrasonic treatment. The quenching medium and aging duration significantly influenced the hardness of Al alloy samples. Peak hardness was achieved after 12 h of artificial aging at the temperature of 140°C. The addition of nano Si3N4 significantly refined the microstructure of unreinforced AA7068. The dispersion of intermetallic compounds (MgZn2) and grain boundary discontinuation were noticed after the T-6 heat treatment. Ultimate tensile strength, yield strength, and hardness were improved by 70.95%, 76.19%, and 44.33%, respectively, with the addition of 1.5 weight % Si3N4 compared to as-cast alloy due to the combined effect of heat treatment, hall-Petch, Orowan, thermal miss match, load-bearing strengthening mechanisms and uniform dispersion of reinforcement. A reduction in percentage elongation was noticed due to composites’ brittle nature by the effect of ceramic Si3N4 particles’ inclusion. The fracture surfaces reveal ductile failure for alloy and mixed-mode failure in the case of composites.