中文摘要：

向AZ91镁合金添加不同含量的稀土铈或镧，研究了它们对镁合金组织结构和腐蚀性能的影响．结果表明，在AZ91镁合金中添加了稀土铈、镧能改善β相分布，起到细化晶粒的作用，并且有少量细小针状的金属间相γ相生成（MgAlRE）．少量的稀土铈和镧加入能明显降低AZ91的析氢速率，使AZ91镁合金的自腐蚀电位负移，自腐蚀电流下降，有效提高AZ91镁合金的耐腐蚀性能．

英文摘要：

AZ91 magnesium alloy with various cerium and lathanum addition is prepared in order to study the effect of rare earth elements on corrosion resistance of the alloy. The results indicate that the Ce or La addition refines the grains of the β phase,while new phase MgA1RE（RE = Ce,La）exists in the alloy and of which the amount increases with the addition amount of Ce or La. The hydrogen evolution of the alloy decreased obviously by addition a few cerium or lathanum elements. The polarization behavior in the 0. 1 mol/L NaC1 solution indicates that Ce or La addition obviously decrease the corrosion current density of the modified AZ91 by 100 times than that of AZ91 magnesium alloy. The corrosion resistance of the Ce or La modified magnesium alloys is markedly improved.