In Situ Confocal Laser Scanning Microscopy of AA2024-T3 Corrosion Metrology

Schneider, Oliver; Ilevbare, G. O.; Kelly, Robert G.; Scully, John R.

doi:10.1149/1.2742804

Cited by 20 publications

(14 citation statements)

References 51 publications

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“…These results are in agreement with the work of Boag et al [19] and Schneider et al [22]. In addition, to have a low Cu/ Fe ratio, as demonstrated previously, it was determined that the Si levels for these particles varied over time.…”

Section: Resultssupporting

confidence: 92%

Localised corrosion of intermetallic particles on aluminium AA2099-T8

Peltier

Thierry

2021

Corrosion Engineering, Science and Technology

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Specimens of AA2099-T8 were immersed for different times ranging from 2 to 180 min in 0.1M NaCl. The development of corrosion around intermetallic particles was studied by scanning electron microscopy (SEM) with energy-dispersive X-ray spectrometry (EDXS). The degradation evolution of each major intermetallic particle after exposure of the alloy to electrolyte allowed to determine which particle corroded during the first stages of immersion. The corrosion of lithium-containing particles was also investigated by transmission electron microscopy (TEM). The earliest stages of attack started with localised corrosion of Al 2 CuMg (S-phase) particles resulting in dealloying which was followed by trenching around these particles. After 10 min, trenching was observed around Al 7 Cu 2 Fe(Mn) particles and then progressed to AlCuFeMnSi particles after 90 min.

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Section: Resultssupporting

confidence: 92%

Localised corrosion of intermetallic particles on aluminium AA2099-T8

Peltier

Thierry

2021

Corrosion Engineering, Science and Technology

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“…The cathodic polarization data was only measured on these three compounds, since they are noted to serve as local cathodes in Al-alloys which they populate in the literature, 2,3,19,[32][33][34][35][36] but also from the data herein as can be gauged from the characteristic potentials of AA7075-T651 as a function of temperature (Fig. 16).…”

Section: Al 2 Cu (θ-Phase)-mentioning

confidence: 99%

Electrochemical Characterization of Intermetallic Phases Common to Aluminum Alloys as a Function of Solution Temperature

Cavanaugh

Birbilis

et al. 2014

J. Electrochem. Soc.

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A practically important scenario in the corrosion of aluminum (Al) alloys is the variation in damage characteristics, i.e. mode, rate and morphology, as function of environmental temperature. In order to address this problem from a mechanistic point of view, this paper presents results for corrosion potentials, pitting potentials and electrochemical characteristics for intermetallic particles commonly present in high strength aluminum alloys, for tests conducted in 0.1M NaCl of varying temperature. Tests were conducted between 0 and 60 • C via the use of a micro-capillary electrochemical cell. The intermetallics investigated were Mg 2 Si, MgZn 2 , Al 7 Cu 2 Fe, Al 2 Cu, Al 2 CuMg and Al 3 Fe. Analysis of the results reveals that the electrochemical behavior of such compounds is heavily dependent on temperature, with ramifications for localized corrosion (and protection) In the most general sense, corrosion represents the adverse intersection between a material and the environment; while in the case of aluminum (Al) alloys, their prescription is widespread and covers many environmental exposure conditions. For a given material, the environment is responsible for the type and extent of corrosion that may result; warranting an investigation of the electrochemical characteristics as function of environment. [1][2][3][4][5][6] In an attempt to unambiguously characterize the mechanistic aspects of localized corrosion of heterogeneously structured high-strength Al-alloys, we have presented the electrochemical characteristics for a number of intermetallic particles and phases common to a large range of such alloys, [7][8][9][10] paying particular attention to the effect of chloride concentration 9 and the effect of solution pH.7 This approach has also recently been followed for investigation of the second phases that occur in magnesium alloys. 11It has been shown that both [Cl − ] and pH have a significant effect upon the corrosion morphology and rate of bulk Al-alloys, as demonstrated for AA7075-T651. 12 Of key relevance to the work herein, it was shown that the resultant alloy corrosion was able to be reconciled in terms of both morphology and rate, from knowledge of the individual electrochemical characteristics of the alloy constituents.13 Furthermore, it is of importance to note that the associated electrochemical kinetics upon alloy constituents is not trivial, in that kinetics may not be accurately predicted based upon composition or knowledge of corrosion potentials alone. However, polarization testing was able to reveal significant quantitative insights allowing a leap in understanding the origins of localized corrosion (and in some cases the absence of localized corrosion). Examples include; spontaneous passivity of Mg 2 Si at alkaline pH and the increase in the ability of Fe-containing intermetallics to sustain ORR as either pH or [Cl − ] increase, to name but a couple of important factors. 7,9 Similarly, such richness is not predicted by methods such as SKPFM, which has been previously used to predict loca...

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“…In one mode of attack whereis the intermetallic is classified as a cathode, the surrounding matrix tends to corrode leaving a ring shape around the particle or also called trenching. There is still some uncertainty on whether or not the trench itself is a result of microgalvanic coupling alone, or if the major contributor is local pH elevation, however a good treatise of this topic was given in a multi-part series of papers by the group at Virginia (Ilevbare, Schneider et al 2004;Schneider, Ilevbare et al 2004;Schneider, Ilevbare et al 2007). In some cases damage may propagate to the base of the particle and eventually lead to particle fall out (Buchheit, Grant et al 1997).…”

Section: The Role Of Microstructure On Corrosionmentioning

confidence: 99%