Ca，Be在镁合金中的阻燃作用

建立了镁合金的晶体，液态及其固/液界面模型.采用递归法计算了Ca，Be在α-Mg、固/液界面、镁液态中的环境敏感镶嵌能，定义并计算了Mg，Ca及Be与氧的原子亲和能.计算结果表明：Ca，Be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Ca，Be扩散到环境能较低的液体中，向液面聚集.由于Ca，Be与氧的原子亲和能低于镁与氧的亲和能，聚集在液体表面的Ca，Be将优先与氧结合，生成致密的镁与合金元素的混合氧化物，阻止镁合金燃烧. 关键词： 电子结构 阻燃 Mg合金

The ignition-proof effect of Ca and Be in Mg alloys

The atomic cluster models of α-Mg，liquid Mg and the interface between liquid/solid have been founded. The environment-sensitive embedding energy of Ca and Be in α-Mg，liquid Mg，liquid/solid interface has been calculated by recursion method. The atomic affinity energy between Mg，Ca，Be with O has been defined and calculated. The calculated results show that the solid solubility of Ca and Be is very small in α-Mg，because of their higher environment-sensitive embedding energy leads to instability in α-Mg crystal. The Ca and Be diffuse in to the liquid Mg, which has lower environment-sensitive embedding energy than the solid，and congregate on the surface of liquid Mg as the alloys solidify. Because the atomic affinity energy of Ca-O and Be-O is lower than Mg-O，The Ca and Be aggregating on the surface of liquid Mg will priorly combined with O，forming compact oxides of Ca，Be and alloys of elements，which prevent Mg alloys from burning.