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采用递归法计算了Nb合金的电子态密度、原子镶嵌能、亲和能和团簇能等电子结构参数,研究Nb合金高温氧化机理.研究表明,氧在Nb合金表面的吸附能较低,易在合金表面吸附,并逐渐扩散到Nb合金的基体中.氧在合金基体中镶嵌能为负值,氧的态密度和Nb相似,在Nb中具有很高的溶解度.Ti,Al在合金晶内的镶嵌能均高于各自在合金表面的镶嵌能,Ti,Al从合金内部向合金表面扩散,最终在Nb合金表面偏聚,形成富Ti,Al的表层.团簇能计算结果表明Nb合金表面的Ti,Al原子各自均有聚集倾向,分别形成Ti和Al原子团.氧与合金表面的Ti,Al,Nb间的亲和能为负数,与三者之间均有相互作用,生成对合金起保护作用的Nb2O5,TiO2,Al2O3组成的混合氧化膜.
Recursive method was used to calculate the electronic density of states, atomic inlay energy, affinity energy and cluster energy and other electronic structure parameters to study the high temperature oxidation mechanism of Nb alloy. The results show that the adsorption energy of oxygen on Nb alloy surface is low, Adsorbed on the alloy surface and gradually diffused into the matrix of Nb alloy.The oxygen inlay in the alloy matrix can have a negative value, the density of oxygen is similar to that of Nb, and has a high solubility in Nb. Of the inlay can be higher than their respective mosaic in the alloy surface, Ti, Al alloy from the interior to the alloy surface diffusion, and finally segregation of the surface of the Nb alloy, the formation of rich Ti, Al surface layer.Cluster can calculate the results show that the Nb alloy surface Of Ti and Al atoms have their own tendency of aggregation and form Ti and Al atomic groups respectively.The affinity between Ti, Al and Nb on the surface of oxygen and oxygen is negative, and the three have interaction with each other, Protective effect of Nb2O5, TiO2, Al2O3 mixed oxide film.