The effect of addition of Mg on microstructure and morphology of Al- 5wt%Al2O3 nanocomposite during mechanical alloying

In the present research the effect of addition of Mg (0 and 20wt%) on the crystallite size, morphology and particles size of Al-5wt%Al2O3 composite during mechanical milling in a high energy planetary ball mill for different milling times up to 20 h were investigated. The phase evolution and crystallite size of milled powders were studied by XRD analysis. The morphology and particles shapes of powders were investigated with SEM. Average particle size of powders was determined by tangential method using SEM micrographs. Results of XRD analysis showed that crystallite size decreases to rang of nanometer with increasing milling time and Mg content. Results of SEM showed that particle size in the samples whit 20 wt% Mg reached to steady state value after about 20 h of milling operation. Addition of Mg to Al matrix leads to reduction of particle size of milled powders at different milling times and accelerates the mechanical milling stages.