Original Article

Fabrication and optimization of AA5754/SiC nanocomposites via friction-stir processing (FSP)

Amirkabir University of Technology, Department of Materials Science and Engineering, Tehran 15875-4413, Iran

^* e-mail: mortezaa.rezaei@yahoo.com
^** e-mail: shamsipur@aut.ac.ir

Received: 17 August 2022
Accepted: 17 January 2023

Abstract

Metal-matrix composites (MMC) are cost-effective alternatives to steel and iron resources. This research investigates the properties of the nanocomposites created by SiC nanoparticles. AA5754 was chosen as a matrix and fabricated by friction-stir processing (FSP). The effects of input parameters, including rotational/traverse speeds, number of passes on the microhardness, and topography, were studied through the response surface methodology. Each parameter was selected in three levels, and other parameters were considered constant. To examine the effect of SiC nanoparticles, optical microscopy (OM), SEM, and microhardness tests were used. Due to the distribution of SiC nanoparticles and homogeneous microstructure coinciding with high microhardness, the optimal rotational speed, traverse speed, and the number of passes at 500 rpm, 20 mm/min, and 3 were obtained, respectively. Also, the average microhardness profile and the average grain size in the SZ region for the optimal sample were equal to 68 Vickers and 1.5 Microns, respectively. The results showed that increasing the number of passes accrued appropriate nanoparticle distribution. During operation, various mechanisms occurred, such as nucleation during recrystallization and placement of SiC nanoparticles at the grain boundaries, which prevent grain boundary migration and inhibit grain growth.