Microstructural, mechanical and thermal properties evaluation of AA6061/Al2O3-BN hybrid and mono nanocomposite surface

Abstract

The fabrication of the hybrid nanocomposite surface using friction stir process (FSP) has recently gained interest in material science researchers and developers due to its superior mechanical and microstructure properties. An AA6061 wrought alloy was used as the base matrix, which is reinforced with Al2O3 and BN ceramics nanoparticles in both hybrid and mono composite surface. The mechanical properties were investigated using a compression and microhardness test; and the highest mechanical properties were obtained for the AA6061/Al2O3-BN hybrid nanocomposite. The stress strain curve showed an improvement in the ultimate stress of the hybrid nanocomposite compared to the base alloy. The microstructures of the synthesized composites were evaluated using optical and scanning electron microscopy (SEM). The FSP has a significant effect on grain refinement where the AA6061 has been refined as receiving alloy by decreasing the grain size by 29 times. Furthermore, equiaxial grains were obtained due to stirring action and FSP pin tool thread design; hence the grain aspect ratio was improved by approximately 400%. The dispersion of the Al2O3 and BN nanoparticles was successfully achieved during the current investigation, as noticed in the SEM examination analysis. Thermal expansion and electrical conductivity were decreased with reinforce the metal matrix with ceramics Al2O3 and BN nanoparticles. Moreover, the hybrid nanocomposite exhibited the minimal values of the thermal expansion and electric conductivity properties.