چكيده به لاتين
In this study, the effect of 1, 1.5 and 2 weight fractions of Al2O3 nanoparticles with average particle size of 40nm, on microstructure and mechanical properties of A356 alloy were investigated. Al2O3 nanoparticles were incorporated into the A356 alloy by argon gas and a mechanical stirrer. Then the effect of Al2O3 nanoparticles content on the microstructure, porosity, hardness, compressive strength and wear properties of the produced nanocomposites were investigated. For microstructural study, field emission scanning electron (FESEM) and optical microscopy (OM) were carried out. Microstructural studies confirmed the successful incorporation and uniform distribution of nanoparticles in the A356 matrix. Also it was revealed that adding Al2O3 nanoparticles, led to a fine microstructure of A356 alloy. According to the results, hardness of A356 alloy was increased from 54 HBN to 73 HBN by adding nanoparticles. Porosity content of the specimens was measured by Archimedes method. The porosity level of nanocomposites increased from 1.3% to 3.2% by increasing weight fraction of nano particles. It concluded that by adding nano alumina particles, compared to A356 alloy, compressive strength increased. One of the samples with optimum properties and a suitable distribiution of nanoparticles in the matrix, was chosen for wear test. The results indicated that by adding nano alumina particles, wear rate greatly reduced. According to the results, dominnat wear mechanism of the nanocomposite samples, was delamination. In the case of unreinforced sample, delamination an adhesive wear mechanism was observed.
