Effect of ZrO2Nanoparticles and Mechanical Milling on Microstructure and Mechanical Properties of Al-ZrO2Nanocomposites

Nano-aluminum powders and nano-ZrO2reinforcement particles were mechanically milled and hot-pressed to produce Al-ZrO2nanocomposites. Microstructure and mechanical properties of Al-ZrO2nanocomposites were investigated using scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) analyses and by performing hardness and compression testing. Uniform particle distribution was obtained up to 3 wt% of nano-ZrO2particles using nano-sized aluminum powders as matrix powders and by applying a mechanical milling process. As the nano-ZrO2reinforcement particles were uniformly distributed in the matrix, the relative density of the Al-ZrO2nanocomposites increased up to 3 wt% nano-ZrO2particles with an increase in milling time; on the other hand, the relative density decreased and the porosity increased with high-weight fractions (>3 wt%) of nano-ZrO2particles due to the negative combined effect of less densification and an increase in the number of particle clusters. The hardness and compressive strength of the Al-ZrO2nanocomposites improved despite increased porosity. However, the compressive strength of Al-ZrO2nanocomposites with a high amount (>3 wt%) of nano-ZrO2particles began to decrease due to the negative combined effect of the less densification of the powder particles and the clustering of nano-ZrO2reinforcement particles. The brittle-ductile fracture occurred in the Al-ZrO2nanocomposites. © 2021 Copernicus GmbH. All rights reserved