Preparation of Ultra Fine-Grained Magnesium Alloy by Mechanical Alloying of AZ31 Chip-Aluminum Powder Mixture

Abstract

To produce magnesium alloy with ultra fine-grain size, powder mixtures, which aluminum powder was added with various contents to turning chips of AZ31 alloy, were mechanically alloyed for various milling times. Micro-structural changes of the mechanically alloyed powder with milling were investigated. Super-saturated solid solutions of the magnesium phase with crystalline size of nanometer scale are formed in the Mg-12 mol%Al and 30 mol%Al powder mixtures mechanically alloyed for long milling time and, especially, it forms the eutectic structure together with Mg 17 Al 12 in the Mg-30mol%Al powder. In the case of the Mg-40 mol%Al and 61.5 mol%Al powders, formation of the intermetallic compounds yields by the mechanical alloying for shorter milling time, and these crystals become to amorphous phase after the prolonged milling time. The harnesses of particles in the powder mechanically alloyed increase with forming of the super saturated solid solution or the intermetallic compound and their refining.