Role of secondary phase particles of 2519A aluminium alloy in localised corrosion

Liu, Ying; Zhang, X. M.; Zhang, H.

doi:10.1179/1432891713z.000000000187

Cited by 7 publications

(4 citation statements)

References 11 publications

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“…6b), which implies a difficult transition to higher energy level for the electrons on the Si-terminal surface, and thus a high work function. 6 In contrast, for MgZn 2 , all the crystal faces have negative Volta potentials, and a negative average Volta potential (−464 mV) indicates that MgZn 2 is anodic relative to pure Al, which is also consistent with the experimental results. 36 Interestingly, for Al 2 CuMg, the Volta potential of (100) surface is 109 mV, in agreement with experimental data listed in Table III.…”

Section: Resultssupporting

confidence: 86%

“…[3][4][5] IMPs containing Cu and Fe, such as Al 2 Cu. 6 and Al 7 Cu 2 Fe, 7 are considered to be cathodic with respect to the matrix, acting as local cathodes and thus promoting cathodic reactions such as oxygen reduction. In contrast, Mg-rich IMPs, such as Al 2 CuMg, are considered anodic relative to the matrix, resulting in selective dissolution and concomitant Cu-enrichment of the IMP.…”

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confidence: 99%

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First-Principle Calculation of Volta Potential of Intermetallic Particles in Aluminum Alloys and Practical Implications

Jin

Liu

Zhang

et al. 2017

J. Electrochem. Soc.

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This work presents a theoretical assessment of galvanic (relative) nobility of four intermetallic particles (IMPs), Al 2 Cu, Al 2 CuMg, Mg 2 Si and MgZn 2 , in aluminum alloys through work function calculation based on density functional theory (DFT). The concepts of work function, Volta potential and relative nobility are discussed with respect to the IMPs and aluminum matrix. The calculated Volta potentials are compared with reported experimental Volta potentials measured by scanning Kelvin probe force microscopy (SKPFM). Various crystal faces and terminal types are examined in the DFT calculation, showing that these two factors have a significant effect on the work function value. Considering the large divergence in the reported experimental data, the comparison shows a general agreement between the calculated and experimental Volta potential data for the investigated IMPs. The DFT calculations provide theoretical explanations for several experimental phenomena. The results demonstrate that DFT calculation is a valuable theoretical approach for assessment of the relative nobility of different phases in the alloys, providing complementary information to experimental data from SKFPM. Moreover, the implications of the calculated Volta potentials are discussed with respect to the corrosion potentials. The addition of various alloying elements into the aluminum (Al) matrix to improve mechanical performance of Al alloys may simultaneously increase their susceptibility to localized corrosion. This is mainly due formation of intermetallic particles (IMPs) that may trigger micro-galvanic corrosion along the interface between the IMPs and the alloy matrix.1 The potential differences between the IMPs and the matrix may result in localized dissolution of the matrix or dealloying of the IMP. 2The most common IMPs present in 2xxx and 7xxx series Al alloys include Al 2 CuMg (S-phase), Al 2 Cu (θ-phase), Al 7 Cu 2 Fe (β-phase), MgZn 2 (η-phase) and Mg 2 Si.3-5 IMPs containing Cu and Fe, such as Al 2 Cu. 6 and Al 7 Cu 2 Fe, 7 are considered to be cathodic with respect to the matrix, acting as local cathodes and thus promoting cathodic reactions such as oxygen reduction. In contrast, Mg-rich IMPs, such as Al 2 CuMg, are considered anodic relative to the matrix, resulting in selective dissolution and concomitant Cu-enrichment of the IMP.8 These localized corrosion events may eventually trigger other corrosion forms, such as stress corrosion cracking or intergranular corrosion.9 Therefore, micro-galvanic corrosion effects between IMPs and the Al matrix is considered to be of utmost importance for the overall service performance of Al alloys.In 1987, Stratmann started to use the Kelvin probe to investigate corrosion properties of metals under thin electrolyte films.10 His measurements revealed a linear relationship between Volta potential and corrosion potential of Cu, Zn, Fe and other metals. Later, the scanning Kelvin microprobe was developed and used for Volta potential measurements of several metals in humid atmospheres.11 Du...

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Section: Resultssupporting

confidence: 86%

mentioning

confidence: 99%

First-Principle Calculation of Volta Potential of Intermetallic Particles in Aluminum Alloys and Practical Implications

Jin

Liu

Zhang

et al. 2017

J. Electrochem. Soc.

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“…Electric double-layer capacitance was then formed at the solid–liquid two-phase interface between the X70 steel specimen and the moisture in the clay particles. A potential difference at this interface led to a potential difference on the surface of the X70 steel, which formed a primary cell that caused localized corrosion [ 60 ]. As shown in Table 7 , as corrosion proceeded, the overall C s value gradually increased.…”

Section: Resultsmentioning

confidence: 99%

Electrochemical Corrosion Behaviour of X70 Steel under the Action of Capillary Water in Saline Soils

Wei

Feng

et al. 2022

Materials

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In this paper, the electrochemical corrosion behavior of X70 steel in saline soil under capillary water was simulated by a Geo-experts one-dimensional soil column instrument. A volumetric water content sensor and conductivity test were used to study the migration mechanism of water and salt (sodium chloride) under the capillary water. The electrochemical corrosion behavior of the X70 steel in the corrosion system was analyzed by electrochemical testing as well as the macroscopic and microscopic corrosion morphology of the steel. The test results showed that the corrosion behavior of X70 steel was significantly influenced by the rise of capillary water. In particular, the wetting front during the capillary water rise meant that the X70 steel was located at the three-phase solid/liquid/gas interface at a certain location, which worsened its corrosion behavior. In addition, after the capillary water was stabilized, the salts were transported with the capillary water to the top of the soil column. This resulted in the highest salt content in the soil environment and the most severe corrosion of the X70 steel at this location.

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“…In contrast, Mg 2 Si, Al 2 CuMg and other anodic particles have negative potentials. Driven by the corrosion potential difference, the microgalvanic corrosion caused by the coupling of these primary particles with the aluminum matrix is an important field to explore the mechanism of microgalvanic corrosion [32,33]. It has been pointed out in many publicly reported literature [34][35][36][37] that Mg 2 Si particles in Al-Mg-Si alloy always undergo accelerated corrosion as local anodes in acidic pH solutions.…”

Section: Micro Corrosion Mechanismmentioning

confidence: 99%

A Review of Research on Galvanic Corrosion of Aluminum Alloys

Zhu¹,

Leng²,

Jin³

et al. 2023

Fluid Dynamics &Amp; Materials Processing

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When aluminum alloys are coupled with dissimilar materials, they often act as corrosion anodes and are suscepted to accelerated corrosion. Therefore, deepening our knowledge of such corrosion phenomena, related mechanisms, and elaborating new prediction model is of great theoretical and practical significance. In this paper, such mechanisms are explained from both macroscopic and microscopic points of view by considering several aspects such as the second phase particle type, grain size, and environmental ions. More specifically, different perspectives on such a problem are elaborated, which take into account: the properties of the coupling pair materials, geometrical characteristics, environmental media characteristics, the corrosion regularity of different types of aluminum alloys, the influence of area ratio on anode corrosion current density, the interference of the solution primary ions represented by Cl-and the accompanying ions represented by Al 3+ . A review is also conducted of the standard test methods used in the study of aluminum alloys galvanic corrosion and of research methods such as the Wire Beam Electrodes Technology (WBE), the Scanning Kelvin Probe Force Microscopy (SKPFM) technology. Finally, three kinds of inhibition technologies are discussed, including the anodic oxidation treatment, the corrosion inhibitor treatment and the coating protection method.

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Role of secondary phase particles of 2519A aluminium alloy in localised corrosion

Cited by 7 publications

References 11 publications

First-Principle Calculation of Volta Potential of Intermetallic Particles in Aluminum Alloys and Practical Implications

First-Principle Calculation of Volta Potential of Intermetallic Particles in Aluminum Alloys and Practical Implications

Electrochemical Corrosion Behaviour of X70 Steel under the Action of Capillary Water in Saline Soils

A Review of Research on Galvanic Corrosion of Aluminum Alloys

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