合金原子对L1_(2)型Al-Zr-X三元铝合金表面电偶腐蚀影响的第一性原理研究  

First-principles Study on the Influence of Alloying Elements on Galvanic Corrosion of Ternary L1_(2)-Al-Zr-X Aluminum Alloys Surface

作　　者：张庆洲 范大伟 刘凌虹[1,2] ZHANG Qinghou;FAN Dawei;LIU Linghong(Hunan Province Key Laboratory of Materials Surface&Interface Science and Technology,Central South University of Forestry and Technology,Changsha,Hunan 410004,China;College of Science,Central South University of Forestry and Technology,Changsha,Hunan 410004,China)

机构地区：[1]中南林业科技大学材料表面与界面科学与技术湖南省重点实验室,湖南长沙410004 [2]中南林业科技大学理学院,湖南长沙410004

出　　处：《计算物理》2023年第6期699-711,共13页Chinese Journal of Computational Physics

基　　金：湖南省自然科学基金(2019JJ40544);湖南省教育厅优秀青年项目(19B587)资助。

摘　　要：本文在AlZr二元合金的基础上,利用第一性原理计算方法,全面计算19种L1_(2)-Al_(x)Zr_(y)X_(z)(X=Pd、Pt、Au、K、Rb、Sr、Ba、Ca、Yb、La、Ce、Y、Er、Sc、Zr、Ti、Cd、Hf、In)三元析出相的(100)、(110)和(111)三种晶面作为表面时的功函数,并分析其与掺杂原子电负性之间的关系,从电子层面阐明掺杂原子对L1_(2)型Al-Zr-X三元铝合金表面电偶腐蚀性能影响的根本原因。通过计算发现不同掺杂晶面暴露为表面时,由于功函数各异,与基体的本征电位差也各不相同。Hg、Cd、Zr、Ti和Hf等掺杂原子能增加析出相(100)表面的功函数,Hg、Cd、In、Ti和Hf等原子能增加析出相(110)面的功函数,而Pd、Pt、Au、In、Sc、Rb、Sr、Yb、Y、Er、K、Ba、La、Ce和Ca原子能降低(111)面的功函数,这些均导致析出相与铝基体的本征电位差进一步减小。此外,结果揭示了掺杂原子电负性与其化合物功函数之间的线性正相关规律。相较而言,电负性与Al接近且替代Al的In、Cd和Hg原子,以及电负性与Zr接近且替代Zr的Ti和Hf原子对析出相功函数影响较小,且其化合物与铝基体的电势差较小,对提升材料抗腐蚀能力有益,其他掺杂原子则对析出相功函数有较大影响。研究解释了部分耐蚀性实验结果,为优化合金成分设计、提升铝合金材料耐腐蚀性提供了理论参考。The galvanic corrosion of aluminum alloy mainly depends on the potential difference between the second phase and matrix. The greater the potential difference, the stronger the corrosion driving force. Based on AlZr binary alloy, we calculated the work functions of the(100),(110) and(111) planes of 19 ternary precipitates L1_(2)-Al_(x)Zr_(y)X_(z)(X=Pd, Pt, Au, K,Rb, Sr, Ba, Ca, Yb, La, Ce, Y,Er, Sc, Zr, Ti, Cd, Hf, In) comprehensively by using the first principle calculations. The relationship between the work functions and the electronegativity of doped atoms was analyzed, and the fundamental reason for the influence of doped atoms on the surface galvanic corrosion performance of L1_(2) type Al-Zr-X ternary aluminum alloy is clarified from the electronic level. Through calculation, we find that when different doped crystal surfaces are exposed to the surface, the potential difference between the phase and the matrix is also different due to the varying work functions. The doped atoms Hg, Cd, Zr, Ti, Hf can increase the work functions of the(100) surface of L1_(2)-Al_(x)Zr_(y)X_(z) ternary precipitates, Hg, Cd, In, Ti, Hf can increase the work function of the(110) surface, and Pd, Pt, Au, In, Sc, Rb, Sr, Yb, Y, Er, K, Ba, La, Ce and Ca could decrease the work function of the(111) surface. These will lead to the further reduction of the potential difference between the phase and matrix. In addition, the linear positive correlation between the electronegativity of doped atoms and the work function of the compound is revealed. In contrast, In, Cd, Hg atoms whose electronegativity is close to Al and doping the site of Al, and Ti, Hf atoms whose electronegativity is close to Zr and doping the site of Zr have less influence on the work function of the phase, and the potential difference between their compounds and aluminum matrix is small, which is beneficial to improving the corrosion resistance of materials. Other doped atoms have greater influence on the work function of the phase. Research results have explained som

关 键 词：电偶腐蚀 铝合金 L1_(2)析出相 合金原子 第一性原理计算 

分 类 号：TG171[金属学及工艺—金属表面处理]