On the role of mechanical milling on structural and morphological features of nano-sized Al3Mg2 powder

Abstract

ABSTRACT Here, Al3Mg2 nanopowder has been made successfully by milling of broken ingot Al3Mg2 for 25 hours. Al3Mg2 ingot was firstly produced from pure Al and Mg by casting. The effect of milling on properties of the obtained powders was studied. The phase identification, crystal size and lattice microstrain of the milled powders were characterized by X-ray diffraction analysis (XRD). The morphology of the powders was investigated by field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). Particle size analysis was utilized for study of Al3Mg2 particle size distributions. The results indicate that the as-broken ingot powder with a wide size distribution of irregular shaped morphology changes to almost equiaxed particles with a narrow size distribution after 25 h milling, reaching an average particle size of <100 nm. Further, the crystallite size of powders decrease with milling while saved lattice strain increases seriously. From XRD graphs, it can be concluded that milling refines the crystallite size, does not modify the crystal structure, and does not introduce contamination. In addition, TEM observations explored the presence of nanocrystalline grain and the diffused rings in related selected area diffraction pattern indicated the formation of high angle grain boundaries and nanostructured β-Al3Mg2 phase.