Corrosion Behavior of Commercial Aluminum Alloy Processed by Equal Channel Angular Pressing

Korchef, Atef; Kahoul, A.

doi:10.1155/2013/983261

Cited by 41 publications

(30 citation statements)

References 44 publications

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“…The constituent particles in an AlMgSi alloy are electrochemically nobler compared to the surrounding aluminum solid solution [16,17,27]. Due to the galvanic coupling between the AlSiFe phases and the surrounding Al matrix in the Cl − -containing test environment, the naturally occurring passivation layer will be reduced and the surrounding aluminum dissolved.…”

Section: Pit Morphologymentioning

confidence: 99%

“…Constituent particles in multi-phase materials mostly act as cathodic inhomogeneity performing a key role in pit initiation and propagation. With an increasing number of ECAP passes, the pitting potential of a variety of multi-phase aluminum alloys, which were reported to increase [11,12,15], decrease [16] or stay unaffected [17]. Correspondingly, for AA 5052, after four ECAP passes, the pitting potential was distinctly shifted to more positive potentials [12].…”

Section: Introductionmentioning

confidence: 97%

“…Fewer pits in the shear band areas were attributed to the microstructural homogenization and refinement of primary particles [6]. The amount, fragmentation and redistribution of constituent particles, containing mostly Si and Fe along with Al, were considered as the main factors for the modified pitting susceptibility and morphology of multiphase alloys [6,11,12,16].…”

Section: Introductionmentioning

confidence: 99%

“…Korchef et al [16] found decreasing pitting potentials explained by the increasing fragmentation of α-AlFeSi particles acting as cathodes and driving anodic dissolution of the surrounding matrix. Jilani et al [17] found no influence on the pitting potential with an increasing number of ECAP passes, but an increasing pitting density and decreasing pit depth.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Effect of Strain Localization on Pitting Corrosion of an AlMgSi0.5 Alloy

Nickel

Dietrich

Mehner

et al. 2015

Metals

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Abstract:The corrosion susceptibility of an age-hardened aluminum alloy in different processing conditions, especially after a single pass of equal-channel angular pressing (ECAP), is examined. The main question addressed is how corrosive attack is changed by strain localization. For that purpose, an AlMgSi0.5 alloy with a strain localized microstructure containing alternating shear bands was subjected to potentiodynamic polarization on a macro-scale and micro-scale using the micro-capillary technique. Pitting potentials and the corrosion appearance (pit depth, corroded area fractions and volumes) are discussed with respect to microstructural evolution due to casting, extrusion and ECAP. Size, shape and orientation of grains, constituent particle fragmentation, cell size and microstrain were analyzed. Stable pitting of shear bands results in less positive potentials compared to adjacent microstructure. More pits emerge in the shear bands, but the pit depth is reduced significantly. This is attributed to higher microstrains influencing the stability of the passivation layer and the reduced size of grains and constituent particles. The size of the crystallographic pits is associated with the deformation-induced cell size of the aluminum alloy. OPEN ACCESSMetals 2015, 5 173

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Section: Pit Morphologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of Strain Localization on Pitting Corrosion of an AlMgSi0.5 Alloy

Nickel

Dietrich

Mehner

et al. 2015

Metals

View full text Add to dashboard Cite

show abstract

“…Grain boundaries are usually associated with an increased electrical resistivity and enhanced atom diffusivity, which may lead to a different electrochemical behaviour, such as anodization and corrosion. However, although they have shown some unusual corrosion behaviours [14][15][16][17] compared to titanium in normal grain size, the anodization behaviours of UFG titanium made by SPD processing have rarely been investigated. To further understand the influence of grain refinement on anodization, a study on the anodization mechanisms of UFG titanium produced by SPD is needed.…”

Section: Introductionmentioning

confidence: 99%

The influence of surface roughness and high pressure torsion on the growth of anodic titania nanotubes on pure titanium

Gao

Starink

2016

Applied Surface Science

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Anodic titanium dioxide nanotube (TNT) arrays have wide applications in photocatalytic, catalysis, electronics, solar cells and biomedical implants. When TNT coatings are combined with severe plastic deformation (SPD), metal processing techniques which efficiently improve the strength of metals, a new generation of biomedical implant is made possible with both improved bulk and surface properties. This work investigated the effect of processing by high pressure torsion (HPT) and different mechanical preparations on the substrate and subsequently on the morphology of TNT layers. HPT processing was applied to refine the grain size of commercially pure titanium samples and substantially improved their strength and hardness. Subsequent anodization at 30 V in 0.25 wt. % NH 4 F for 2 hours to form TNT layers on sample surfaces prepared with different mechanical preparation methods was carried out. It appeared that the local roughness of the titanium surface on a microscopic level affected the TNT morphology more than the macroscopic surface roughness. For HPTprocessed sample, the substrate has to be pre-treated by a mechanical preparation finer than 4000 grit for HPT to have a significant influence on TNTs. During the formation of TNT layers the oxide dissolution rate was increased for the ultrafine-grained microstructure formed due to HPT processing.

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A Simple Surface Treatment for Mg to Gain Enhanced Resistance to Corrosion and Corrosive Wear by Hammering Al Powder‐Covered Mg Substrate

Tang

et al. 2022

Adv Materials Inter

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rendering it widely utilized for cellular phones and notebook computers in recent years. The earth crust contains 2.1% mass of Mg, [5] making this abundant metal available for a wide range of applications. However, magnesium has shortcomings, including high chemical reactivity or low resistance to corrosion and others such as wear and creep. [6] Significant efforts have been made to modify Mg-based alloys by alloying appropriate elements [7] or modify the surface of Mg or Mg alloys [6] for improved performance. Surface modification of Mg or Mg alloys is an economical and effective approach for enhanced resistance to corrosion and wear.There are many processes for coating a more durable layer on the outmost surface of a base material for desired properties. The coating materials can be metallic, ceramic, or polymeric, depending on the application. For Mg or Mg alloys, different surface methods have been studied and used, e.g., pack vacuum diffusion, [8,9] salt bath, [10,11] cold/ thermal spray, [12][13][14] laser processing, [15,16] chemical vapor deposition, [17,18] and physical vapor deposition, [19,20] electrodeposition, [21,22] and chemical conversion coating, [23,24] etc. These techniques can improve the corrosion resistance of Mg to different extents. However, some of the techniques need costly equipment or involve complicated processes. For example, vacuum chamber and pumping system as well as gas lines are required for physical vapor deposition. For less expensive techniques such as electrodeposition, one needs to deal with electrolyte preparation, wet process, electrolyte recycling, etc. For chemical conversion coating process, which is also a wet process, different factors need to be handled, e.g., chemical solution preparation, waste solution recycling, and control of various process parameters such as temperature, pressure, and solution ion concentrations. [24] This work shows a simple approach to increase the resistance of Mg to corrosion and corrosive wear by generating a nanocrystalline aluminum layer on Mg surface, which is achieved by repeated punching or hammering an Al powdercovered Mg substrate. Al is also a light metal with excellent passivation capability. A thin Al layer on the Mg substrate can significantly increase its resistance to corrosion and corrosive Mg is abundant in the earth crust and very attractive as a base metal of lightweight alloys for the transportation industry due to its high strengthto-weight ratio. However, Mg is prone to corrosion, which largely limits its widespread applications. Here, a very simple surface treatment method is demonstrated for enhanced resistance to corrosion and corrosive wear by hammering Al powder-covered surface of Mg with subsequent recovery treatment. Such treated surface is examined with X-ray diffraction technique for information on phases, nanocrystallization, thickness, and coverage of the Al layer. Structure of the Al layer and lattice imperfections are analyzed with transmission electron microscopy. Electrochemical behavior, corrosion, and...

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Corrosion Behavior of Commercial Aluminum Alloy Processed by Equal Channel Angular Pressing

Cited by 41 publications

References 44 publications

Effect of Strain Localization on Pitting Corrosion of an AlMgSi0.5 Alloy

Effect of Strain Localization on Pitting Corrosion of an AlMgSi0.5 Alloy

The influence of surface roughness and high pressure torsion on the growth of anodic titania nanotubes on pure titanium

A Simple Surface Treatment for Mg to Gain Enhanced Resistance to Corrosion and Corrosive Wear by Hammering Al Powder‐Covered Mg Substrate

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