Effects of TiO2, CuO, and SiO2 nanoparticles addition on the microstructure and mechanical properties of Al-10 wt% Zn alloy

Abstract

This paper presents the effects of adding TiO2, CuO, and SiO2 (1 wt%) nanoparticles on the microstructure and mechanical properties of Al-10 wt% Zn alloy. A set of composite alloys was produced by incorporating SiO2, CuO, and TiO2 nanoparticles to the Al-10 wt% Zn alloy. Optical microscope (OM), scanning electron microscope (SEM) fitted with an Energy Dispersive Spectroscope (EDS), and X-ray diffraction (XRD) were used to investigate the microstructure of these alloys. The mechanical properties of the composite solders were assessed using the Vickers hardness tests. After a solution heat treatment at 500 K for 2 h, samples were immediately aged at 373 to 473 K for 2 h, followed by water quenching at 300 K. The experimental data indicated that Al-10 wt% Zn-1wt% SiO2 samples had the highest hardness values among all investigated composite alloys. The calculated porosity percentages of the composite alloys revealed that the Al-10 wt% Zn-1 wt% SiO2 samples had the lowest percentage. This finding can be attributed to the fact that these samples demonstrated the highest hardness values. The hardness of all composite alloys decreased with increasing the aging temperature with anomalous behavior at 443 K, where they had abnormally high values. The observed differences in the mean crystallite size, lattice strain, and dislocation density of the composite alloys, calculated from XRD data with increasing aging temperature, are attributed to the precipitation in Al-Zn alloys. The calculated values of the stress exponent and activation energy of composite alloys may be associated with grain boundary diffusion (GBD) as the dominant operating mechanism.