Investigation of tribological and compressive behaviors of Al/SiO2 nanocomposites after T6 heat treatment

Abstract

The aim of this paper is to present experimental results of tribological and compression properties of aluminum nanocomposites after T6 heat treatment. This heat treatment contained three stages: solutionizing at 500°C for 5 h, quenching in water, and ageing 180°C for 9 h. The method of nanocomposite production was the stir casting process. The SiO2 nanoparticles in 0.5 and 1% wt were added to the aluminum melt as the reinforcement agent. The microstructural evaluation was conducted by the optical microscopy (OM) and the field emission scanning electron microscopy (FESEM) methods. The results of the wear test revealed that the specific wear rate of specimens comprising SiO2 nanoparticles was lower than that of specimens without nanoparticles. Thus, the formation of the holes, wear debris and cracks decreased obviously for nanocomposite surfaces during wear testing. Moreover, the wear rate reduced obviously for nanocomposites fabricated by the pre-heating process compared to others. It was noticeable that the ball-milling process was an effective method to decrease the friction coefficient value to 0.15 for nanocomposites. Such observations were due to higher hardness and lower micro-porosity content. The elastic modulus for various nanocomposites improved by 8–19% compared to the aluminum alloy. In addition, when the content of SiO2 nanoparticles increased from 0.5 to 1% wt, the ultimate compressive strength decreased about 11–13% due to the presence of more micro-porosities.