Evaluation of tensile strength and elastic modulus of 7075-T6 aluminum alloy by adding SiC reinforcing particles using vortex casting method

Abstract

In this study, an experimental analysis for the mechanical properties of 7075-T6 aluminum reinforced with SiC particles with three different sizes of nanometer, submicron and micron scales is performed. The composites are made by vortex casting method. Standard tensile test specimens are fabricated by CNC machining. Finally, according to the standard, the tensile experimental test is performed on the selected samples. To perform the tensile test, first the specimens are fixed in the jaws of the device and then at a velocity of 0.2 mm/min is applied, until the specimens are failed. The base alloy in micro scale is examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM) images. Field emission scanning electron microscopy (FESEM) images are also used to show the distribution of nanoparticles in the base and it is found that the size of nanoparticles in the base is less than 100 nanometers. SEM images and X-ray diffraction spectroscopy (EDS) analysis results show the presence of phases (Al-Cu-Fe), (Al-Fe), (Al-Fe-Si) and phases ƞ (MgZn2), S (Al2CuMg) in 7075-T6 aluminum alloy. In general, by adding reinforcing particles to aluminum, the ultimate tensile strength increases, except for micron particles with a 5 wt%. This is while the percentage of elongation of composites compared to 7075 aluminum is decreased. Among the nanoparticle-sized specimens, the specimen with 1 wt% of reinforcing particles improved the ultimate tensile strength, which is equivalent to 21.33%. Submicron and micron particles-reinforced specimens, the 2 wt% specimen, improved the ultimate tensile strength about 16.10% and 11.65%, respectively. Hence, it can be concluded that the particles in nanoscale has more effect on the tensile strength of the composite structure.