Fracture of oxide films on strained aluminium

Edeleanu, C.; Law, T. J.

doi:10.1080/14786436208212625

Cited by 49 publications

(16 citation statements)

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“…Al oxide as well as other metallic oxide materials display reduced ductility when compared to their pure metallic counterparts. Oxide layers fracture and lead to failure, as shown for instance in an early work on thin Al films . There must be a critical oxide thickness where there is a transition from this cracking behavior observed at the micron scale to the assisted-ductility behavior observed at the nanoscale.…”

Section: Discussionmentioning

confidence: 97%

“…Oxide layers fracture and lead to failure, 52 as shown for instance in an early work on thin Al films. 53 There must be a critical oxide thickness where there is a transition from this cracking behavior observed at the micron scale to the assisted-ductility behavior observed at the nanoscale. Our oxide layer is amorphous, while macroscopic layers are polycrystalline, and fracture is aided by grain boundaries and crystal plasticity in the oxide.…”

Section: ■ Conclusionmentioning

confidence: 99%

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Molecular Dynamics Simulations of Aluminum Foams under Tension: Influence of Oxidation

2018

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For materials with high surface-to-volume ratio and high oxygen affinity, oxide layers will significantly change the material properties. However, oxidation effects have not been studied for metal nanofoams, which have many applications because of their light weight and high stiffness. We use molecular dynamics simulations to show that oxidized aluminum nanofoams possess significantly improved ductility without reduction in tensile strength. The Al−O interface leads to an increased defect nucleation rate at the oxide interface, preventing localized deformation. At the same time, the enthalpy of mixing between aluminium and oxygen decreases for increasing O concentrations, reaching a minimum at the stoichiometric ratio of Al 2 O 3 , resulting in stabilized bonds and increased strength.

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Section: Discussionmentioning

confidence: 97%

Section: ■ Conclusionmentioning

confidence: 99%

Molecular Dynamics Simulations of Aluminum Foams under Tension: Influence of Oxidation

2018

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“…In the proposed mechanism, the carrier concentration is essentially independent of temperature, whereas the carrier mobility is a thermally activated process. This conduction mechanism is similar to that proposed for LixNil-xO and other transition metal oxides (2,3) and is often referred to as a "hopping" process. Munakata proposed a "hopping" model for electrical conduction in the vanadate glasses (4).…”

Section: Research and Development Laboratories Corning Glass Work mentioning

confidence: 84%

Deformation of Anodic Oxide Films

Bubar

Vermilyea

1966

J. Electrochem. Soc.

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Tantalum oxide films on smooth, pure substrates can be deformed as much as 50% before fracture. On surfaces containing impurity particles the films contain many flaws which nucleate cracks after relatively little deformation. Zirconium oxide films showed some evidence of deformation, but much less than tantalum oxide. Aluminum oxide films showed no evidence of deformation.Protection against corrosion is usually afforded by a thin film of reaction product. The behavior of such a film during deformation of the underlying metal would be of great importance in determining corrosion under such conditions and may play a decisive role in stress corrosion cracking and corrosion fatigue. It is usually assumed that reaction films are brittle, and one currently popular theory of stress corrosion cracking asserts that repeated cracking of the passive film allows continued corrosion. Bradhurst and Leach (1) have shown that barrier-type anodic oxide films on aluminum are brittle, while Edeleanu and Law (2) have demonstrated that both porous anodic aluminum oxide films and the natural corrosion film on aluminum are brittle. Young (3), on the other hand, reported that anodic films on tantalum changed color during deformation of the metal indicating some deformation of the oxide, and Dunn (4) has told us that anodic films on tantalum deform along with the substrate when tantalum sheet is rolled. In this paper we report the use of a new technique to obtain quantitative information about the deformation of anodic films on aluminum, zirconium, and tantalum.

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“…films.--The idealized case of two current transitions discussed previously is well represented by A1203 films, which deform little or not at all during deformation of the substrate aluminum (17,18), because there is a new area with near zero thickness of oxide and a retained old area covered with oxide of the initial thickness. The reanodization method of analysis was applied to cold rolled specimens with either 15 or 100v anodic films.…”

Section: Plastic Deformation Of Nonporous A1203 and Ta205mentioning

confidence: 99%

Information on Anodic Oxides on Valve Metals: Oxide Growth at Constant Rate of Voltage Increase

Dunn

1968

J. Electrochem. Soc.

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The formation of nonporous anodic oxide films is treated mathematically for the constant rate of voltage increase method to provide a basis for interpreting reanodization current-voltage curves. Illustrative reanodization I-V curves are considered for such initial anodic oxide films as nonporous oxide, porous A1203, plastically deformed A1203 and Ta2Os, and annealed nonporous A1203. Evidence obtained for pore filling in and the conversion of a porous film into a nonporous film is supported by electron microscopy and thickness measurements. Confirmation of low ductility in At203 and high ductility in Ta20~ is obtained. Information is provided on the restoration of ionic conductivity in A120~, which is lost by annealing. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.122.253.228 Downloaded on 2015-05-28 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.122.253.228 Downloaded on 2015-05-28 to IP Vol. 115, No. 2 ANODIC OXIDES ON VALVE METALS 221 ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.122.253.228 Downloaded on 2015-05-28 to IP Vol. 115, No. 2 ANODIC OXIDES ON VALVE METALS 225 ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.122.253.228 Downloaded on 2015-05-28 to IP

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Fracture of oxide films on strained aluminium

Cited by 49 publications

References 1 publication

Molecular Dynamics Simulations of Aluminum Foams under Tension: Influence of Oxidation

Molecular Dynamics Simulations of Aluminum Foams under Tension: Influence of Oxidation

Deformation of Anodic Oxide Films

Information on Anodic Oxides on Valve Metals: Oxide Growth at Constant Rate of Voltage Increase

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