(1．江蘇理工學(xué)院 材料工程學(xué)院，常州 213001；
2．中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 運用第一原理平面波贗勢方法計算L12-Al3Li金屬間化合物點缺陷的形成焓，并結(jié)合Wagner–Schottky模型，研究L12-Al3Li金屬間化合物在523、673、823和1 000 K時點缺陷濃度與成分之間的關(guān)系。結(jié)果表明：在這4個溫度下，L12-Al3Li金屬間化合物中Al空位濃度最小，Li空位濃度次之，Al反位和Li反位的缺陷濃度較大。Al反位和Li反位缺陷濃度在理想金屬間化合物Al3Li化學(xué)計量比成分處基本相同，不過兩種反位的缺陷濃度隨著合金成分相對于化學(xué)計量比成分的偏離而變化顯著，在富Al端Al反位缺陷濃度較大，在富Li端Li反位缺陷濃度較大。運用Arrhenius方程計算點缺陷的有效形成焓，結(jié)果顯示Al反位和Li反位的有效形成焓較小且基本相同，Li空位次之，Al空位最大。
關(guān)鍵字: Al3Li金屬間化合物；第一原理計算；點缺陷濃度；形成焓；Wagner–Schottky模型
（1. School of Materials Engineering, Jiangsu University of Technology, Changzhou 213001, China;
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:Based on the first-principle pseudopotential plane-wave method, the formation enthalpies of point defects for L12-Al3Li intermetallic were calculated. Combining with Wagner–Schottky model, the point defect concentrations in L12-Al3Li at 523, 673, 823 and 1 000 K as function of composition were also investigated. The results show that the point defect concentrations at these investigated temperatures from small to big in sequence are Al vacancy, Li vacancy, Al anti-site and Li anti-site. The point defect concentrations of Al anti-site are similar to those of Li anti-site in stoichiometric L12-Al3Li composition. However, the point defect concentrations of Al anti-site and Li anti-site change evidently when the alloy composition is deviated from the stoichiometric L12-Al3Li composition, resulting in mainly Al anti-site in rich-Al alloy and mostly Li anti-site in rich-Li alloy. Using Arrhenius equation, the effective formation enthalpies of point defects for L12-Al3Li were calculated. It is found that the effective formation enthalpies from big to small in sequence are Al vacancy, Li vacancy, Al anti-site and Li anti-site.
Key words: Al3Li intermetallic; first-principle calculation; point defects density; formation enthalpy; Wagner–Schottky model
