Variation of Rare Earth Elements in the Magnesium Alloy ME21 for the Sheet Production

Sheet properties of magnesium like ductility, strength and corrosion resistance are improved by alloying with rare earth elements. This paper reports on the variation of the rare earth elements in the aluminum-free magnesium alloy ME21 (2 wt% Mn and 1 wt% RE) in order to investigate the sensitivity to the amount and kind of the rare earth elements regarding strength and ductility. The paper will show the results of casting and rolling experiments of some alloy variations of ME21 which contain different amounts of Cerium based misch metal and Neodymium. The influence of these different alloying elements on the microstructure of the billets before and after heat treatment is shown. Furthermore, rolling trials with different schedules were conducted and the mechanical properties of the sheets are presented and discussed with respect to arising textures and the average grain sizes. The results of this casting and rolling trials are used to discuss how to tailor the mechanical properties of the magnesium alloy ME21.