铝铜合金的晶界偏析行为及析出相的理论研究  

Theoretical study on segregation behavior of grain boundaries and precipitated phases in Al-Cu alloys

作　　者：何卫 马恒[3] 石泽灏 王利民 柯定芳 汤超[1,2] 肖伟 薛博育 王建伟[4] HE Wei;MA Heng;SHI Zehao;WANG Limin;KE Dingfang;TANG Chao;XIAO Wei;XUE Boyu;WANG Jianwei(State Grid Electric Power Research Institute Co.,Ltd.,Nanjing 211106,China;Wuhan NARI Limited Liability Company,State Grid Electric Power Research Institute,Wuhan 470004,China;Zhejiang Huadian Equipment Testing Institute Co.,Ltd.,Hangzhou 310015,China;State Key Laboratory of Nonferrous Metals and Processes(GRINM Group Co.,Ltd.),Beijing 100088,China)

机构地区：[1]国网电力科学研究院有限公司,南京211106 [2]国网电力科学研究院武汉南瑞有限责任公司,武汉470004 [3]浙江华电器材检测研究院有限公司,杭州310015 [4]有色金属材料制备加工国家重点实验室(有研科技集团有限公司),北京100088

出　　处：《材料科学与工艺》2022年第2期68-74,共7页Materials Science and Technology

基　　金：国家电网公司科技指南项目(SGZJ0000KXJS1900221)。

摘　　要：晶界偏聚行为及析出相形成对铝铜合金的力学性能提升至关重要。为研究铝铜合金中Cu元素与Al基体的相互作用,本文基于密度泛函理论,利用第一性原理方法计算了Al∑5(210)[001]晶界Cu元素的偏析能、电荷密度分布等性质,并结合AFLOW的高通量框架系统研究了不同铝铜二元析出相的晶格常数、形成能和弹性常数等信息。晶界模拟结果表明,由于尺寸效应和成键性质的变化,Cu原子在晶界上形成能更低,更易于偏聚到晶界GB2位置,偏聚能为-0.42 eV。高通量计算结果验证了在不同Cu浓度下,铝铜二元体系中会产生大量形成能为负的亚稳相,以及4种稳定的基态结构AlCu_(3),Al_(4)Cu_(9),AlCu和Al_(2)Cu。以上4种化合物的形成能分别为-0.19,-0.21,-0.20,-0.18 eV/atom,与铝基体相比,其体弹性模量和剪切模量分别提高约20%和90%。The segregation behavior and precipitate formation of grain boundaries are important to improve the mechanical properties of Al-Cu alloys.In order to investigate the interaction between Cu element and Al matrix in Al-Cu alloys,the first-principles method based on the density functional theory(DFT)was adopted to investigate the properties of segregation energy and charge density distribution of Cu element at Al∑5(210)[001]grain boundary in this work.Combined with the high-throughput framework of AFLOW,the lattice constants,formation energies,and elastic constants of different Al-Cu precipitates were systematically studied.Grain boundary simulation results show that due to the size effect and the variation of bonding characters,the formation energy of Cu atoms on the grain boundary was lower,and it was easier to segregate to the GB2 position of the grain boundary with a segregation energy of-0.42 eV.Results of high-throughput calculations verified that with the variation of Cu concentration,there were a large number of metastable phases with negative formation energies and four most stable ground state structures in Al-Cu binary systems,i.e.AlCu_(3),Al_(4)Cu_(9),AlCu,and Al_(2)Cu.The formation energies of the above four compounds were-0.19,-0.21,-0.20,and-0.18 eV/atom,respectively.The bulk elastic modulus and shear modulus of the four compounds increased by about 20%and 90%,compared with those of aluminum matrix.

关 键 词：晶界 密度泛函理论 偏析行为 铝合金 Al_(x)Cu_(y)二元化合物 

分 类 号：TG111.2[金属学及工艺—物理冶金] TG146.2[金属学及工艺—金属学]