Mg-La和Mg-Nd二元合金相稳定性的第一原理研究  

FIRST-PRINCIPLES STUDY ON THE PHASE STABILITY OF Mg-La AND Mg-Nd BINARY ALLOYS

作　　者：张会[1] 王绍青[1] 

机构地区：[1]中国科学院金属研究所沈阳材料科学国家(联合)实验室,沈阳110016

出　　处：《金属学报》2012年第7期889-894,共6页Acta Metallurgica Sinica

基　　金：国家重点基础研究发展计划项目2011CB606403;中国科学院"十一五"信息化专项"超级计算环境建设与应用"项目INFO-115-B01资助~~

摘　　要：La和Nd是镁合金中常用的稀土添加元素,为了帮助理解它们在Mg合金中的强化机制,应用第一原理计算方法,研究了Mg-La和Mg-Nd二元合金的相稳定性.计算结果表明,Mg-La和Mg-Nd合金在Mg_(12)RE和Mg_3RE之间的平衡相分别为Mg_(17)La_2和Mg_(41)Nd_5;La和Nd在Mg中的溶解度大小差别较大,表明者在镁合金中产生强化的机理不同;Mg_3Nd具有比Mg_(12)La更大的弹性模量,因而具有更好的强化效果.The applications of magnesium poor high-temperature creep resistance, which can alloys in automobile industry are limited by their be effectively improved by rare earth （RE） elements addition. In general, rare earth elements are introduced as mixtures of various kinds of metals, and all of the elements are considered to behave in the same way. In practice, various rare earth elements may act differently in magnesium alloys. La and Nd are the two elements usually added to magnesium alloys. In this paper, first-principles calculations are made to investigate the phase stability of Mg-La and Mg-Nd binary alloy systems. In addition, the solubility of La and Nd in Mg is discussed and the elastic constants of the strengthening phases in Mg-La and Mg-Nd alloys are calculated. The equilibrium phases between Mgz2RE and Mg3RE are MglTLa2 and Mg41Nd5 for Mg-La and Mg-Nd systems respectively. The difference of calculated solubility for La and Nd in Mg indicates the distinct strengthening mechanism for these two alloy systems. Mg3Nd is predicted to have larger elastic moduli and a better strengthening effect than Mg12La.

关 键 词：第一原理 镁合金 稀土元素 

分 类 号：TG146.22[一般工业技术—材料科学与工程]