Investigation on microstructure, mechanical properties and tribological behavior of AlZnMgCu1.5-T6/zirconia surface nanocomposites developed by FSP

Abstract

This research aimed to find the suitable condition for the fabrication of AlZnMgCu1.5-T6/ZrO2 nanocomposites to improve the mechanical properties and wear resistance of the produced surface nanocomposites. The effects of rotational speed and the number of passes were investigated to obtain the desired properties. For this purpose, rotational speeds of 1000 rpm, 1200 rpm, and 1400 rpm were used along with a constant traverse speed of 40 mm/min, and the number of processing passes was considered to be one and two passes. Optical microscopy and electron microscopy equipped with an EDS system were used to study the microstructural evolution, such as grain refinement and distribution of nanoparticles in these nanocomposites. To evaluate the mechanical and wear properties of the nanocomposites, tension, hardness, and wear tests were performed according to related standards. In the next step, the fracture surfaces were examined by XRD to investigate the formation of possible phases. Finally, fracture and wear surfaces were investigated to determine dominant mechanisms. In addition to the absence of defects, an extreme grain refinement due to the severe plastic deformation of the grains and the presence of ceramic nanoparticles were confirmed by microscopic observations. According to the results, due to the extreme grain refinement and the presence of ZrO2 hard ceramic nanoparticles, the average and maximum hardness values increased up to 33% and 48%, respectively, compared to those of the aluminum alloy matrix. Also, the wear rate was reduced up to 65%. It was concluded that according to the findings, the most suitable condition for achieving the optimal mechanical and wear properties is 1400 rpm-two passes.

Keywords

• Surface nanocomposite
• Friction stir processing
• AlZnMgCu1.5-T6 alloy
• ZrO2 nanoparticles
• Tool rotational speed
• Number of passes