(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(diǎn)實(shí)驗(yàn)室，長沙 410083)
摘 要: 基于第一性原理密度泛函方法，計(jì)算研究Al/θ′共格界面對應(yīng)變時效參數(shù)的能量響應(yīng)，綜合討論外加單向應(yīng)變、時效溫度以及Cu化學(xué)活度對界面形成能的影響作用。結(jié)果表明：θ′相的界面能隨溫度的升高而增大，當(dāng)溫度從298 K增加到498 K時，大尺寸的θ′相界面能(γAl/θ′)增大約2.3%，而小尺寸的富銅θ′相界面能(γAl/θ′(Cu-rich))增大約7.6%；在相同溫度和應(yīng)變下，小尺寸的富銅θ′相界面能總是比大尺寸θ′的相界面能低約10%。在室溫下，當(dāng)應(yīng)變從0增加到2%時，富銅θ′相界面能最大降低約9.2%；不同的應(yīng)變方式(壓縮或拉伸、垂直或平行界面方向)對各類型θ′相界面能的作用效果有所不同，由此影響到其在基體中的析出方式，這應(yīng)該是應(yīng)變時效的主要機(jī)制之一。
關(guān)鍵字: Al/θ′界面；界面能；應(yīng)力-應(yīng)變時效；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
