X-ray study of the kinetics of mechanical alloying

Elemental powder mixtures of Fe50Mn50, Fe70Ni30, and Cu50Cr50 compositions were milled in hermetic vials of planetary ball mill. Phase composition and crystalline structure of powders were determined by X-ray diffraction. For Fe50Mn50 and Fe70Ni30, the formation of single-phase alloy was completed after 30 min of processing, whereas for Cu50Cr50 composition, milling for 4 h has not resulted in the formation of single-phase alloy. The X-ray diffraction patterns indicate that the density of crystalline lattice defects increases with milling time. The effect of ball's diameter on the crystalline structure of mechanically alloyed powders was investigated. The obtained results were discussed on the base of the "grain boundary" model of mechanical alloying.