研究了复合添加稀土(Y,Nd)含量(1%~4%)对AZ81镁合金微观组织和力学性能的影响。结果表明,适量稀土元素的加入使AZ81镁合金的组织明显细化,β(Mg17Al12)相减少,同时析出了粒状的化合物Al2Y,Al2Nd。经固溶时效处理后,随着复合稀土含量的增加,在室温、150℃和250℃3个温度下,合金的强度和延伸率基本上呈先升后降的趋势。当稀土含量为2%时,合金的室温强度和150℃高温强度同时达到最大值,分别为282MPa和212MPa;在各温度下稀土含量为2%时延伸率最好。 The effects of rare earth (Y, Nd) content (1% ~ 4%) on the microstructure and mechanical properties of AZ81 magnesium alloy were studied. The results show that the microstructure of AZ81 magnesium alloy is obviously refined and the β (Mg17Al12) phase is reduced with the addition of appropriate amount of rare earth elements, while the granular compounds Al2Y and Al2Nd are precipitated simultaneously. After solution treatment and aging treatment, with the increase of RE content, the strength and elongation of the alloy basically increased first and then decreased at three temperatures of 150 ℃ and 250 ℃. When the content of rare earth is 2%, the room temperature strength and the high temperature strength of 150 ℃ reach the maximum at the same time, which are respectively 282MPa and 212MPa. The elongation is best when the content of rare earth is 2% at each temperature.