On Favorable Alloying Elements for Mg-Zr System Alloys

Abstract

When one of the components Ag, Bi, Ca, Cd, Ce, Cu, Li, Misch metal, Sn, Ti and Zn were contained in magnesium as alloying elements, the solubility of Zr in the melt of such a magnesium alloy and the effects of soluble Zr in the molten alloy on the cast structures were studied and the possibility of production of intermetallic compounds by the alloying elements and Zr over the solubility limit in the molten alloys was investigated by X-ray analysis. The results obtained were as follows: The solubility of Zr at 700° was about 0.5∼0.6% in Mg-Ag-Zr, 0.45% in Mg-Bi-Zr, 0.5% in Mg-Ca-Zr, 0.55∼0.6% in Mg-Cd-Zr, 0.5∼055% in Mg-Ce-Zr, 0.4∼0.5% in Mg-Cu-Zr, 0.35∼0.5% in Mg-Li-Zr, 0.55∼0.6% in Mg-Misch metal-Zr, 0.45% in Mg-Ti-Zr, 0.75∼0.8% in Mg-Zn-Zr and considerably decreased in Mg-Sn-Zr by increase of Sn. The grain-refining effect of Zr on the cast structure depended on the quantity of Zr soluble in the molten magnesium alloy. Intermetallic compounds of the alloying elements and Zr were obtained as Mg-Cu-Zr and Mg-Sn-Zr when Zr was over the solubility limit in the molten alloy.