Production of a nanocrystalline composite of Al–4% Cu/SiC by a mechanical milling method

Aluminum powders with an average particle size of 45 μ m and copper with a particle size of <60 μ m were used to produce a solid solution of Al–4 Cu. The effect on the formation time of solid solution and changes in internal strain and the aluminum lattice parameter of adding SiC particles to the milling was studied. The results showed that the addition of 10% SiC to the powder mixture reduced alloying of the Al–4% Cu solution from 10 to 4 h, which would accelerate the process of mechanical alloying. Moreover, when the milling time was increased to 10 h, the average size of primary crystals was reduced from 81 to 21 nm; when SiC was added to the powder mixture the crystallite size was further reduced, with the average size reaching 16 nm. The initial strain also rose from 0.18% to 0.67% and the initial strain of the powder mixture containing 10% SiC reached 0.76%. The resulting powder was evaluated by x-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD results were used to determine the average size of the crystals, the lattice parameter and the internal strain and the SEM images were used to investigate changes in morphology, shape and particle size of the powder. (paper)