镁合金稀土阻燃机理电子理论研究  

Theoretical study of ignition-proof mechanism of RE element in Mg alloys

作　　者：刘贵立[1] 

机构地区：[1]沈阳工业大学建筑工程学院,沈阳110023

出　　处：《物理学报》2008年第1期434-437,共4页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:50671069);辽宁省教育厅科学研究计划(批准号:05L297);沈阳市科技计划(批准号:1041020-1-04-6)资助的课题~~

摘　　要：通过计算机软件建立镁合金的晶体,液态及其固/液界面模型.采用递归法计算了稀土元素在α-Mg、固/液界面、镁液态等原子环境中的环境敏感镶嵌能,定义并计算了Mg,La及Y与氧的原子亲和能.计算结果表明:La,Y在镁晶体中的环境敏感镶嵌能较高,不能稳定固溶于晶体中,因此在固体中的溶解度较小.合金凝固时稀土元素扩散到环境能较低的液体中,向液面聚集.由于稀土与氧的原子亲和能低于镁与氧的亲和能(镁、稀土与氧的亲和能分别为Mg-O:-14.9338eV,La-O:-19.0608eV,Y-O:-19.5050eV),聚集在液体表面的稀土将优先与氧结合,生成致密的稀土氧化物,阻止镁合金燃烧.The atomic cluster models of a-Mg, liquid Mg and the interface between liquid/solid have been founded by computer program. The environment-sensitive embedding energy of RE elements in a-Mg, liquid Mg, liquid/solid interface has been calculated by recursion method. The atomic affinity energy between Mg, La, Y with O has been defined and calculated. The calculated results show that the solid solubility of La and Y is very small in a-Mg, because their higher environment-sensitive embedding energy leads to instability in a-Mg crystal. The RE elements diffuse to the liquid Mg, which has lower environment-sensitive embedding energy than the solid, and congregate on the surface of liquid Mg as the alloy solidifies. Because the atomic affinity energy of RE-O is lower than Mg-O（The atomic affinity energy between Mg, La, Y with O are Mg-O： -14.9338eV,La-O： -19.0608 eV,Y-O： -19.5050 eV, respectively）, the RE elements congregating on the surface of liquid Mg will priorily combined with O, forming compact RE oxides, which prevent Mg alloys from burning.

关 键 词：电子结构 阻燃 MG合金 

分 类 号：TG146.22[一般工业技术—材料科学与工程]