中文摘要：

运用第一原理平面波赝势方法计算L12-Al3Li金属间化合物点缺陷的形成焓,并结合Wagner–Schottky模型,研究L12-Al3Li金属间化合物在523、673、823和1 000 K时点缺陷浓度与成分之间的关系。结果表明：在这4个温度下,L12-Al3Li金属间化合物中Al空位浓度最小,Li空位浓度次之,Al反位和Li反位的缺陷浓度较大。Al反位和Li反位缺陷浓度在理想金属间化合物Al3Li化学计量比成分处基本相同,不过两种反位的缺陷浓度随着合金成分相对于化学计量比成分的偏离而变化显著,在富Al端Al反位缺陷浓度较大,在富Li端Li反位缺陷浓度较大。运用Arrhenius方程计算点缺陷的有效形成焓,结果显示Al反位和Li反位的有效形成焓较小且基本相同,Li空位次之,Al空位最大。

英文摘要：

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 Llz-AlaLi 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 L1E-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.