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采用第一原理平面波赝势方法,结合Wagner-Schottky缺陷热力学模型,研究金属间化合物L10-TiAl中各种空位和反位点缺陷的形成焓、热力学平衡浓度及其相互作用等。结果表明:这些缺陷的热力学平衡浓度均随温度的升高而增大,其中反位缺陷浓度均高于空位缺陷浓度,Ti空位浓度高于Al空位浓度。在理想化学计量比成分下,Ti反位缺陷的浓度与Al反位缺陷的基本相当;在略偏离计量比的富Ti成分端,Ti反位缺陷的浓度高于Al反位缺陷的;在富Al成分端则相反。不同点缺陷之间均普遍存在相互排斥性,难以聚集,将倾向于向基体中分散和扩散。
The first-principles plane-wave pseudopotential method and Wagner-Schottky defect thermodynamic model were used to study the formation enthalpies, thermodynamic equilibrium concentrations and their interactions of various vacancy and anti-site defects in the intermetallic compound L10-TiAl. The results show that the thermodynamic equilibrium concentrations of these defects increase with the increase of temperature. The concentration of anti-phase defects is higher than that of vacancies, and the concentration of Ti vacancies is higher than that of Al vacancies. Under the ideal stoichiometric composition, the concentration of Ti anti-phase defect is almost the same as that of Al anti-phase defect. At the Ti-rich component slightly deviated from the metric ratio, the concentration of Ti anti-phase defect is higher than that of Al anti- The opposite of the Al composition ends. Defects between different points are generally mutually exclusive, difficult to gather, will tend to disperse and spread to the matrix.