Application of Finite Element Modeling to Macro-Galvanic Coupling of AA7050 and SS316: Validation Using the Scanning Vibrating Electrode Technique
Application of Finite Element Modeling to Macro-Galvanic Coupling of AA7050 and SS316: Validation Using the Scanning Vibrating Electrode Technique
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DOI：
10.1149/1945-7111/ac55ce
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发表时间：
2022-03-01
影响因子：
3.9
通讯作者：
Kelly, Robert G.
中科院分区：
文献类型：
--
作者：
Charles-Granville, Utibe-Eno;Marshall, Rebecca S.;Kelly, Robert G.
采用扫描振动电极技术（SVET），在实际紧固件偶件暴露表面的典型环境中，通过实验验证有限元模型（FEM）在模拟与SS 316偶件耦合的AA 7050宏观电偶腐蚀中的适用性。从AA 7050-SS 316偶件样品最初暴露的SVET环境中修改了FEM边界条件，以便更好地代表局部腐蚀倾向AA 7050的稳态腐蚀表面。更好的协议之间的SVET衍生的数据和模型的情况下，宏观电流耦合行为，实现了近中性条件下，相比酸性条件。用经验证的模型确定电极/电解质界面处的电流密度。此外，观察到SVET探针高度处测得的电流密度与电极表面处测得的电流密度之间的百分比差异与电极表面处的电流密度的大小成比例，其中在电偶界面处观察到的差异最大。从SVET导出的数据的模型预测的偏差的似是而非的原因进行了讨论。
The scanning vibrating electrode technique (SVET) was utilized to experimentally validate the applicability of finite element modeling (FEM) in simulating macro-galvanic-induced corrosion of AA7050 coupled to SS316, in environments representative of the boldly exposed surface of an actual fastener couple. The FEM boundary conditions were modified from the SVET environments in which the AA7050-SS316 couple sample was initially exposed, in order to better represent the steady-state corroding surface of the localized corrosion-prone AA7050. Better agreements between the SVET-derived data and the model in the case of macro-galvanic coupling behavior were achieved for near-neutral conditions, compared to acidic conditions. The current density at the electrode/electrolyte interface was determined with the validated model. In addition, the percent difference between the measured current density at the SVET probe height and that at the electrode surface was observed to scale with the magnitude of current density at the electrode surface, with the largest discrepancy seen at the galvanic couple interface. Plausible reasons for the deviation of the model predictions from the SVET-derived data are discussed.