(清华大学 机械工程系， 北京 100084)
摘 要: 在镁合金废料经过熔剂精炼后，依次添加0.05%~0.9%混合稀土，考察混合稀土对合金液净化效果的影响。 结果表明： 镁合金液中夹杂的体积分数由0.6%以上降低至0.2%以下。 分析认为混合稀土的加入减少了合金液的氧化，反应形成了含稀土氯化物和氧化物的夹杂与镁合金液具有较大的密度差， 有利于夹杂的沉降去除。 因此， 添加适量混合稀土可以起到净化镁合金液的作用。
关键字: 镁合金； 混合稀土； 净化
（Department of Mechanical Engineering， Tsinghua University， Beijing 100084， China ）
Abstract: Recycling of magnesium alloy AZ91D scraps produced by die casting was discussed. To estimate the effects of rare earths on the magnesium alloy melt purifying, 0.05%-0.9% mixture rare earths were added step-by-step to the melt after flux refining. The results show that the volume fraction of inclusions in the magnesium alloy varies from over 0.6% to under 0.2%. The mixture rare earths additions decrease the AZ91D melt oxidation and that the heavier inclusions including REClx and RExOy are easier to sink. Therefore, proper rare earths addition can purify magnesium alloys.
Key words: magnesium alloy; mixture rare earths; purification
