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根据固体与分子经验电子理论(EET),采用键距差法(BLD),分析并计算了C11b型金属间化合物MoSi2的价电子结构与理论键能;采用合金元素Al部分取代MoSi2晶格中的Si原子,依据固体与分子经验电子理论在代位式固溶体中的平均原子模型,分析并计算了C11b型Mo(Si0.95,Al0.05)2的价电子结构与理论键能。结果表明:Al微合金化改变了Mo原子和Si原子的杂化状态,从而使相应的价电子结构参数发生变化。与MoSi2相比,Mo(Si0.95,Al0.05)2固溶体中共价电子数在总价电子数中所占的比例(η)由65.87%降至64.28%,因而Al微合金化不利于MoSi2强度的提高;但是晶格电子数由4.7141增至4.9202,所以Al微合金化有利于MoSi2塑性的改善。
The valence electron structures and theoretical bond energies of the C11b intermetallic compound MoSi2 were analyzed and calculated by the bond distance difference method (BLD) based on the empirical electron theory of solids and molecules (EET). The Al element was partially substituted for the MoSi2 lattice Si atom, the valence electron structure and theoretical bond energy of C11b-type Mo (Si0.95, Al0.05) 2 were analyzed and calculated according to the average atomic model of solid-state and empirical electron theory in the substitutional solid solution. The results show that Al microalloying changes the hybrid state of Mo atom and Si atom, and the corresponding valence electron structure parameters change. Compared with MoSi2, the ratio of the number of covalent electrons in the total amount of electrons in the solid solution of Mo (Si0.95, Al0.05) 2 (η) decreased from 65.87% to 64.28%, so Al microalloying was not conducive to MoSi2 However, the number of lattice electrons increases from 4.7141 to 4.9202, so Al microalloying is beneficial to the improvement of MoSi2 plasticity.