Crystal Structure Formed in Mechanical Alloying Process of Mg-Al-Zn Powder Mixture Using Magnesium Alloy Machined Chips

Abstract

For making the functional alloy powder from magnesium alloy scrap, Mg-Zn and Mg-Al-Zn powder mixtures, which aluminum and zinc powder were added with various contents to machined chips of AZ31 alloy, were mechanically alloyed for various milling times using planetary ball mill. Crystal phase formed in the obtained powder was investigated by X-ray di ff raction and Vickers hardness of the powder particles was measured for confirmations of the formed phases. In the case of Mg-2.5 mol%Zn powder mechanically alloyed for long milling time, super-saturated α -Mg phase with 2.5 mol%Zn concentration forms. The structures of Mg-28 and 52 mol%Zn powder consist of Mg 2 Zn 2 or MgZn 2 , Mg 7 Zn 3 phases and then these phases become to amorphous phase by milling for prolonged time. In the ternary Mg-Al-Zn system of composition range, which were (30-50) mol%Mg with Al / Zn = (90 / 10-60 / 40) molar ratio, Mg-(30-50) mol%Al-20 mol%Zn and Mg-(10-30) mol%Al-40 mol%Zn, icosahedron Mg 49 (Al,Zn) 32 phase as called the quasi crystal forms by the mechanical alloying for 72 ks.