(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083；
2. 中南大學(xué) 有色金屬材料科學(xué)與工程教育部重點實驗室，長沙 410083；
3. 江蘇理工學(xué)院 材料工程學(xué)院，常州 213001)
摘 要: 采用第一原理平面波贗勢方法，結(jié)合Wagner-Schottky缺陷熱力學(xué)模型，研究金屬間化合物L(fēng)10-TiAl中各種空位和反位點缺陷的形成焓、熱力學(xué)平衡濃度及其相互作用等。結(jié)果表明：這些缺陷的熱力學(xué)平衡濃度均隨溫度的升高而增大，其中反位缺陷濃度均高于空位缺陷濃度，Ti空位濃度高于Al空位濃度。在理想化學(xué)計量比成分下，Ti反位缺陷的濃度與Al反位缺陷的基本相當(dāng)；在略偏離計量比的富Ti成分端，Ti反位缺陷的濃度高于Al反位缺陷的；在富Al成分端則相反。不同點缺陷之間均普遍存在相互排斥性，難以聚集，將傾向于向基體中分散和擴(kuò)散。
關(guān)鍵字: L10-TiAl金屬間化合物；點缺陷濃度；形成焓；第一原理；Wagner-Schottky模型
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering,
Ministry of Education, Central South University, Changsha 410083, China;
3. School of Materials Engineering, Jiangsu University of Technology, Changzhou 213001, China）
Abstract: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 L10-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.
Key words: L10-TiAl intermetallic composite; point defect concentration; formation enthalpy; first principles; Wagner-Schottky model
