Exfoliation Corrosion and Pitting Corrosion and Their Role in Fatigue Predictive Modeling: State-of-the-Art Review

Hoeppner, David W.; Arriscorreta, Carlos A.

doi:10.1155/2012/191879

Cited by 42 publications

(21 citation statements)

References 106 publications

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“…The boehmite is nucleated at dislocation centers or pores at the surface of the amorphous oxide film [55]. Then, the boehmite film growth occurs by ionic diffusion through the oxide lattice.…”

Section: Discussionmentioning

confidence: 99%

Significant Corrosion Resistance in an Ultrafine-Grained Al6063 Alloy with a Bimodal Grain-Size Distribution through a Self-Anodic Protection Mechanism

Oskooie

Asgharzadeh

Sadighikia

et al. 2016

Metals

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Abstract:The bimodal microstructures of Al6063 consisting of 15, 30, and 45 vol. % coarse-grained (CG) bands within the ultrafine-grained (UFG) matrix were synthesized via blending of high-energy mechanically milled powders with unmilled powders followed by hot powder extrusion. The corrosion behavior of the bimodal specimens was assessed by means of polarization, steady-state cyclic polarization and impedance tests, whereas their microstructural features and corrosion products were examined using optical microscopy (OM), scanning transmission electron microscopy (STEM), field emission scanning electron microscopy (FE-SEM), electron backscattered diffraction (EBSD), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) techniques. The bimodal Al6063 containing 15 vol. % CG phase exhibits the highest corrosion resistance among the bimodal microstructures and even superior electrochemical behavior compared with the plain UFG and CG materials in the 3.5% NaCl solution. The enhanced corrosion resistance is attributed to the optimum cathode to anode surface area ratio that gives rise to the formation of an effective galvanic couple between CG areas and the UFG matrix. The operational galvanic coupling leads to the domination of a "self-anodic protection system" on bimodal microstructure and consequently forms a uniform thick protective passive layer over it. In contrast, the 45 vol. % CG bimodal specimen shows the least corrosion resistance due to the catastrophic galvanic corrosion in UFG regions. The observed results for UFG Al6063 suggest that metallurgical tailoring of the grain structure in terms of bimodal microstructures leads to simultaneous enhancement in the electrochemical behavior and mechanical properties of passivable alloys that are usually inversely correlated. The mechanism of self-anodic protection for passivable metals with bimodal microstructures is discussed here for the first time.

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Section: Discussionmentioning

confidence: 99%

Significant Corrosion Resistance in an Ultrafine-Grained Al6063 Alloy with a Bimodal Grain-Size Distribution through a Self-Anodic Protection Mechanism

Oskooie

Asgharzadeh

Sadighikia

et al. 2016

Metals

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“…The absence of many examples of pitting can be explained by the large number of grain boundaries exposed by the pit. The pit initiates intergranular corrosion that progresses into exfoliation and obliterates evidence of the pit [13,14]. Table 1 shows the mechanical properties summary of the tensile specimens cut from the corroded medium scale test panels and the tensile specimens that have undergone the same mechanical processes but have not been exposed to the corrosion environment.…”

Section: Representative Cross Sections Of the Medium Scale Testmentioning

confidence: 99%

Effect of Partial Cladding Pattern of Aluminum 7075 T651 on Corrosion and Mechanical Properties

Rendell

Hsiao

Shirokoff

2017

Advances in Materials Science and Engineering

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The corrosion resistance of aluminum 7075 T651 in full clad (Alclad), partial clad, and bare (unclad) forms was compared after 300 hours of corrosion exposure in an acidic salt spray cabinet test at 36 ∘ C. After corrosion exposure, severe to moderate exfoliation corrosion was observed on the unprotected medium sized test panel, light general corrosion was observed on the partially clad panel, and patches of corrosion not penetrating the clad layer were observed on the fully clad panel. After corrosion tests, the tensile strength of partially clad, fully clad, and unprotected panels decreased by 3.4%, 4.0%, and 5.3%, respectively.

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“…Corrosion fatigue studies were first reported by Haigh in 1917(Haigh 1917 and followed by McAdam, 1926-1930(McAdam 1926a, b, 1927, 1929. Gough and Sopwith (1932a, b, 1935a, b, 1946a published extensively on it from 1932 to 1946.…”

Section: Scientific Fundamentalsmentioning

confidence: 99%

Coatings for Biomedical Applications

Hauert¹,

Falub²,

Thorwarth³

et al. 2013

Encyclopedia of Tribology

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DefinitionCapillary force and surface wettability are related phenomena happening at the interfaces of solid, liquid, and air phases, and are highly dependent upon the interaction between liquids and solid surfaces. Scientific Fundamental Surface WettabilityWhen a liquid is in contact with a solid surface in air, in general, a droplet of the liquid will be formed. The shape of the droplet depends upon the interaction between the liquid and the solid surface. If the interaction is strong, i.e., the liquid "likes" the surface, the liquid drop will be "flat." On the contrary, if the interaction is weak, i.e., the liquid "hates" the surface, it will "bead up." Scientifically, such a property is described quantitatively by the concept of contact angle, which demonstrates the angle (y) at which the air-liquid and solid-liquid interfaces meet (see Fig. 1). Such a situation is the result of the force balance at the location where air, liquid, and solid phase meet, the socalled "three phase contact line." The interfacial tension of air-liquid, air-solid, and liquid-solid interface is denoted by g al , g as , and g ls , respectively. The force balance is described by the well-known Young's equation (Blake 1993; Butt et al. 2003; Isrealachvili 2003):This is a clear description of the interaction between the solid and liquid, as a smaller value of contact angle exhibits a larger difference between g as and g ls and, therefore, a much lower interfacial tension between the solid and liquid.The contact angle measurement is also an informative way to show the surface wettability of a liquid on a solid surface. If the interaction between the liquid and the solid surface is strong, a much lower interfacial energy results, and, as a result, the surface will be covered more by the liquid so that more area with higher air-solid interfacial energy is replaced by much lower interfacial energy of the liquid and solid. The result is that the liquid droplet is more spread out and has a lower value of contact angle. On the other hand, an unfavorable interaction between the liquid and solid surface generates a higher interfacial energy and, therefore, the system will maximize the area of the solid-air interface and minimize that of the interface between the liquid and solid surface. Consequently, the liquid forms a droplet with a small footprint on the surface and has a higher value of contact angle.

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Exfoliation Corrosion and Pitting Corrosion and Their Role in Fatigue Predictive Modeling: State-of-the-Art Review

Cited by 42 publications

References 106 publications

Significant Corrosion Resistance in an Ultrafine-Grained Al6063 Alloy with a Bimodal Grain-Size Distribution through a Self-Anodic Protection Mechanism

Significant Corrosion Resistance in an Ultrafine-Grained Al6063 Alloy with a Bimodal Grain-Size Distribution through a Self-Anodic Protection Mechanism

Effect of Partial Cladding Pattern of Aluminum 7075 T651 on Corrosion and Mechanical Properties

Coatings for Biomedical Applications

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