Dry Milling of Aluminum and Ceramic Nanoparticles for a Particulate-Injection Casting of Aluminum Matrix Nanocomposites

Nanocomposites of aluminum matrix reinforced with nanomaterials made using conventional casting techniques usually contain an incomplete dispersion of nanoparticles in the matrix. Recently, the use of aluminum powders for the entrance of nanoparticles into the melt by semi-solid particulate-injection casting has been examined to improve the dispersion of nanoparticles. In this study, A356–1 wt% SiC and A356–1 wt% Al2O3 nanocomposites were produced using this mentioned method and the results were compared with the nanocomposites reinforced with the same amount of SiC and Al2O3 nanoparticles but without the addition of aluminum powders. The experimental results indicated that even without having any pre-treatment on the as-received nanoceramics, they will be dispersed to some extent in the matrix owing to semi-solid shear stress introduced via the rotation of the stirrer. However, it was found that the ball milling process with aluminum powders was effective for increasing the number of isolated nanopowders dispersed in the matrix, although some large clusters of nanopowders were detected that counteracted the otherwise potentially useful effects of the increased dispersion of single nanoparticles.