Compressive Behavior of a High-Strength Al-Based Nanocomposite Reinforced with Magnesium Aluminide Nanoparticles

In this work، a new aluminum matrix nanocomposite reinforced with beta-magnesium aluminide nanoparticles was produced by powder metallurgy technique. The prealloyed Al-40 wt. % Mg intermetallic ingot was milled for 100 hours to synthesize β-Al3Mg2 nanoparticles with the average size of 25 nm. Different amounts of nanoparticles were added to Al matrix powder and the mixture was then milled for 10 hours. Al/β-Al3Mg2 nanocomposite samples were prepared by hot pressing of the composite powders in a uniaxial die at 400 °C under the constant pressure of 600 MPa for 2 hours. The results of density measurements revealed that both the density and relative density of nanocomposite samples decrease due to the usage of superlight β-Al3Mg2 reinforcement. Mechanical properties of the nanocomposites were significantly improved with increasing the reinforcement content. Increasing the amount of β-Al3Mg2 nanoparticles continuously improved the hardness and yield strength of composites from 35 BHN and 87 MPa for pure aluminum to approximately 176 BHN and 625 MPa for the sample containing 20 wt. % β-Al3Mg2 nanoparticles، respectively. However، the addition of more reinforcement particles up to 20 wt. % resulted in a decrease in the ultimate strain of the samples، and hence، 10 wt. % nanoparticles was considered to be the optimum content of the reinforcement component