Synthesis and characterization of high volume fraction Al–Al2O3 nanocomposite powders by high-energy milling

Al–Al2O3 metal matrix composite (MMC) powders with volume fractions of 20, 30, and 50% Al2O3 were synthesized by high-energy milling of the blended component powders. The particle sizes of Al2O3 studied were 50 nm, 150 nm, and 5 μm. A uniform distribution of the Al2O3 reinforcement in the Al matrix was successfully obtained after milling the powders for a period of 20 h at a ball-to-powder ratio of 10:1 in a SPEX mill. The uniform distribution of Al2O3 in the Al matrix was confirmed by characterizing these nanocomposite powders by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray mapping, and X-ray diffraction (XRD) techniques.