Papers by Author: D.X. Tang

Abstract: The relationship between structure, ionic radius and electronegativity and solubility of the various rare-earth elements in Mg was studied. It is found that light RE(La-Sm, Eu, Yb) have more complicated phase relation with Mg but the heavy RE(Gd-Lu, Sc) have the similar crystal structure with magnesium. Also it is found that the less electronegativity difference between Mg and RE is, the more solubility limit of RE in Mg is. The fact of the RE solubility decreased in magnesium with lowering temperature suggests that there is a possibility of Mg supersaturated solid solution formation and it will decomposition during aging. According to the rule, an megnesium alloy with higher strength feature was developed. Their mechanical properties are UTS 347MPa, YTS 290MPa and elongation 12.5% at room temperature.

Abstract: A new series of magnesium-rare earth master alloys have been developed by the electrowinning method with subsidence cathode in the KCl•NaCl-RECl3 system. The electrolysis conditions were studied. Experimental results showed that the optimum for electrolyte at 850oC and 10~20wt% RECl3 content in the molten salt system. The current efficiency of electrolyte increased with increasing the rare earth content and reach the maximum at the content of 20% RECl3. The current efficiency gradually decreased with increasing cathode current density. The component of master-alloys was analyzed using ICP-MS and chemical method. A series of magnesium-rare earth master-alloy, Mg-Y, Mg-Nd, Mg-Ce, Mg-La, Mg-Nd-rich and Mg-LPC were successfully prepared and the content of rare earth is adjustable between 5 – 20%.