CAJ | 학술논문

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。
채용제일원리평면파안세방법，결합Wagner-Schottky결함열역학모형，연구금속간화합물L10?TiAl중각충공위화반위점결함적형성함、열역학평형농도급기상호작용등。결과표명：저사결함적열역학평형농도균수온도적승고이증대，기중반위결함농도균고우공위결함농도，Ti공위농도고우Al공위농도。재이상화학계량비성분하，Ti반위결함적농도여Al반위결함적기본상당；재략편리계량비적부Ti성분단，Ti반위결함적농도고우Al반위결함적；재부Al성분단칙상반。불동점결함지간균보편존재상호배척성，난이취집，장경향우향기체중분산화확산。
Using the plane wave pseudopotential method in first-principles and Wagner-Schottky model, the formation enthalpies, equilibrium concentrations, and interaction of vacancies and anti-site point defects were assessed for L1 0?TiAl intermetallics. The results show that, in the whole composition range of interest, all the defect concentrations increase with increasing temperature. In particular, the anti-site defect concentrations are higher than the vacancy defect concentrations, and the Ti vacancy concentration is higher than the Al vacancy concentration. At the stoichiometric composition, the Ti anti-site defect concentration is comparable to that of Al anti-site defect. At the Ti-rich side, the Ti anti-site defect concentration is higher than that of Al anti-site defect, while at the Al-rich side, the Al anti-site defect concentration is higher than that of Ti anti-site defect. The interaction between these defects is essentially repulsive, which facilitates the defect distribution and diffusion in the matrix.