(1. 中南大学 材料科学与工程学院，长沙 410083；
2. 中南大学 有色金属材料科学与工程教育部重点实验室，长沙 410083)
摘 要: 基于第一性原理密度泛函方法，计算研究Al/θ′共格界面对应变时效参数的能量响应，综合讨论外加单向应变、时效温度以及Cu化学活度对界面形成能的影响作用。结果表明：θ′相的界面能随温度的升高而增大，当温度从298 K增加到498 K时，大尺寸的θ′相界面能(γAl/θ′)增大约2.3%，而小尺寸的富铜θ′相界面能(γAl/θ′(Cu-rich))增大约7.6%；在相同温度和应变下，小尺寸的富铜θ′相界面能总是比大尺寸θ′的相界面能低约10%。在室温下，当应变从0增加到2%时，富铜θ′相界面能最大降低约9.2%；不同的应变方式(压缩或拉伸、垂直或平行界面方向)对各类型θ′相界面能的作用效果有所不同，由此影响到其在基体中的析出方式，这应该是应变时效的主要机制之一。
关键字: Al/θ′界面；界面能；应力-应变时效；第一性原理
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials, Ministry of Education, Central South University,
Changsha 410083, China）
Abstract:Based on first-principles, the potential effects of coherent Al/θ′ interfaces under the response to external strains were calculated, and the effect of the uniaxial strain, aging temperature and Cu activity on the interfacial energies of both stoichiometric and Cu-rich Al/θ′ interfaces energies were investigated. The results show that the interfacial energies θ′ phase always increase with temperature increasing, the larger size interface energy (γAl/θ′) and smaller size interface energy (γAl/θ′(Cu-rich)) increase by about 2.3% and 7.6%, respectively, as the temperature increases from 298 to 498 K. Under the same temperature and strain states, γAl/θ′(Cu-rich) is always lower than γAl/θ′ by about 10%. For a parallel tensile strain of 2% at room temperature, γAl/θ′(Cu-rich) decreases the most by up to about 9.2%. The different strain signs (compressive or tensile) and directions (parallel or vertical) have different influences on the interface energies, and can affect the orientation preference of θ'''' precipitates in the matrix. This may be one major mechanism for stain/stress aging.
Key words: Al/θ′ interface; interface energy; strain-stress aging; first-principles
