Abstract
The wear resistance and microhardness behavior of hybrids consisting of wrought aluminum alloy AA7075 with different volume fractions of SiC and BN nano-powders were investigated experimentally. The surfaces of the hybrid nanocomposites were fabricated by friction stir processing (FSP). The microstructure of the reinforcement nano-powders and fabricated nanocomposite surface were examined using scanning electron microscopy (SEM) and high-resolution polarized optical microscopy. The wear resistance and microhardness tests were performed on the specimens before and after the fabrication process. The AA7075 showed a large grain size with an average of 178 mu m, while the hybrid composites of AA7075/SiC-BN showed finer grains with an average size of 8 mu m due to the FSP parameters. Additionally, a good nano-particle surface dispersion was clearly visible with nearly no voids. The wear resistance results showed that the addition of SiC and BN nano-particles increased the fabricated nanocomposite surface wear resistance by 53-61%. It was also noted that the wear resistance rate had a clearly inverse relationship with the increasing mass fraction of the nano-particles. The presence of SiC and BN nano-particles also increased the hardness by an average of 45%. The volume fraction of the reinforced nanoparticles had a significant impact on the mechanical and wear properties of the fabricated hybrid nanocomposite surfaces.