Production of AA7075/ZrO2 nanocomposite using friction stir processing: Metallurgical structure, mechanical properties and wear behavior

Abstract

AA7075-T6 alloy has the highest strength among aluminum alloys, but the presence of relatively weak surface properties such as hardness and wear properties has limited its use in some industries. In this research, friction stir processing and the addition of ZrO2 nanoparticles have been employed to enhance the surface properties. The rotational speeds of 1000 and 1200 rpm and traverse speed of 40 mm/min were selected for the processing. Microstructural studies were performed using light and electron microscopes, and all the samples were subjected to hardness and tensile tests. Finally, the fracture surfaces of the samples were examined using x-ray diffraction test. Using appropriate variables led to the creation of defect-free macro and microstructures. Thanks to the grain refinement that occurred during the process and the presence of hard ceramic nanoparticles, the hardness and wear properties were improved. In total, with the addition of nanoparticles, it was observed that the microhardness increased up to 48%, and the wear rate decreased up to 62% compared to those of the base metal.