The effect of nanoparticle content on the microstructure and mechanical properties of ZA27-Al2O3-Gr hybrid nanocomposites produced by powder metallurgy

In this study, ZA27-Al2O3-Gr hybrid nanocomposite materials (HNMs) were prepared by powder metallurgy method including mechanical-milling and hot-pressing (HP). The physical and mechanical properties of ZA27-Al2O3-Gr HNMs have been investigated with the primary objective of understanding the influence of the alumina (Al2O3) nanoparticle (n-Al2O3) reinforcement. The density, hardness and tensile strength tests of HNMs carried out to determine the physical and mechanical properties of ZA27-Al2O3-Gr HNMs. Scanning Electron Microscope (SEM) is used for the microstructural evolution of the HNMs. As a result of microstructure examination results, n-Al2O3 were observed around grain boundary while the graphite (Gr) nanoparticles (n-Gr) were dispersed homogeneous throughout ZA27 matrix. Relative density values decreased with the increase of nanoparticle reinforcement ratio from 1%vol to 4%vol., while an increase in porosity values was detected for HNMs. Moreover, the results showed that the addition of n-Al2O3 significantly improved the mechanical properties of the HNMs. Additionally, the HNMs reinforced with 4%vol. n-Al2O3 and 1%vol. n-Gr exhibited the highest tensile strength of about 158 MPa and hardness of 160 HB in comparison with the other HNMs reinforced with different content of n-Al2O3.