Fabrication and Characterization of Magnesium-Based Nanocomposite Discs Reinforced with Al2O3 Nanoparticles

Abstract

Magnesium (Mg)-based nanocomposites are increasingly used for different applications, including the mechanical and aeronautical industries. In this paper, double-sided pressing was used to fabricate the nanocomposite discs. Various physical properties and the microstructure of these nanocomposites, reinforced with 1.5%, 3%, and 5% aluminum oxide (Al₂O₃) nanoparticles, were investigated and compared with the case of pure Mg powder without nanoparticles. Nanocomposite discs were prepared at 250, 500, and 750 MPa, and then sintered at 450 °C for one hour under an atmosphere of argon (99.995%) and hydrogen (0.005%). The density, microhardness, and wear rate of the nanocomposite specimens were carefully evaluated and discussed. Polarization curves were plotted to examine the corrosion rate of the nanocomposite discs. The microstructures of the nanocomposite discs were evaluated using a scanning electron microscope (SEM). The results showed that, due to the uniform dispersion of nanoparticles in the Mg powder, the reinforcement of 3% Al₂O₃ nanoparticles in the nanocomposite discs led to high microhardness and corrosion resistance. The cases with 5% Al₂O₃ showed the accumulation and agglomeration of nanoparticles at grain boundaries, resulting in a reduction of microhardness and wear resistance compared to the ones with 3% nanoparticles.