Autonomous filling of creep cavities in Fe-Au alloys studied by synchrotron X-ray nano-tomography

Fang, H.; Versteylen, C. D.; Zhang, S.; Yang, Yiying; Cloetens, Peter; Ngan-Tillard, D.J.M.; Brück, E.; Zwaag, Sybrand van der; Dijk, Niels van

doi:10.1016/j.actamat.2016.09.023

Cited by 35 publications

(70 citation statements)

References 43 publications

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“…The height of the creep cavity directly scales with the cavity radius a with h/a = (1 − cos ψ)/ sin (ψ) ≈ 0.77. Throughout the simulations the nominal concentration is chosen to be c 0 = 0.01, with an edge concentration of c 1 = 0.0001, in order to reflect the experimental situation for self healing in Fe-Au alloys [6,7,9]. As a consequence, the supersaturation c is comparable to the nominal concentration c 0 .…”

Section: Methodsmentioning

confidence: 99%

“…It was found that the creep cavity growth and the precipitate growth directly affect the strain rate of the alloys. Additional scanning electron microscopy studies indicated a close similarity between the precipitation mechanism at the outer surface [10], compared to the precipitation on the creep cavity surface within the material [9].…”

Section: Introductionmentioning

confidence: 99%

“…Zhang and coworkers subsequently demonstrated that precipitation of substitutional solute leads to the self healing of creep cavities in Fe-Au and Fe-Mo alloys [6][7][8]. The creep defects and repairing precipitates were studied in detail for Fe-Au self-healing creep alloys, using X-ray nanotomography [9]. It was found that the creep cavity growth and the precipitate growth directly affect the strain rate of the alloys.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Finite element modelling of creep cavity filling by solute diffusion

Versteylen

Szymanski

Sluiter

et al. 2018

Philosophical Magazine

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Finite element modelling of creep cavity filling by solute diffusion

Versteylen

Szymanski

Sluiter

et al. 2018

Philosophical Magazine

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“…As the creep cavities nucleate in the nanometer size range and reach a size of about a micron by the time the filling is complete a high‐resolution tomography technique is required. In Figure , experimental nanobeam X‐ray tomography data are shown for creep‐failed samples of the solutionized Fe–Au alloy …”

Section: Autonomous Healingmentioning

confidence: 99%

Section: Autonomous Healingmentioning

confidence: 99%

Self‐Healing Phenomena in Metals

Dijk

Zwaag

2018

Adv Materials Inter

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puters) would not be possible in their current form without highly developed metallic materials.Currently all metallic materials are developed along the so-called "damage prevention" paradigm, [1] i.e., their composition and microstructure are optimized such that the initiation and propagation of mechanical damage (in the form of internal damage such as pores or surface initiated cracks) leading to catastrophic failure of the product is postponed as much and as long as possible. Such a performance needs a careful tuning of the constituent atoms forming the matrix and its secondary phases, the grain size and the dislocation structure in the "pristine" state. Of course, the word "pristine" state is somewhat a misnomer as engineering metals generally have undergone multiple thermomechanical treatments once casted and are in a far-from-equilibrium state. Yet, in this context "pristine" metallic products are those in the shape and condition at the start of their life in an actual construction. All current metallic engineering materials have in common that once a local crack or defect is generated, either by the preceding plastic deformation or simply by mechanical overload of the material, this damage will remain forever and could be the initiator of the final catastrophic fracture event. In simple mathematical termsTypical examples of such an accumulation of microscopic damage leading to macroscopic failure are (low and high cycle) fatigue as well as creep failure. Generally speaking metallic systems perform very well under such conditions due to the high bond strength between the metallic atoms as well as a stable dislocation network, which tend to keep the atoms more or less in place or at least in registry, even in case of severe loading or deformation.The same positive attributes responsible for the excellent mechanical properties of metals are also the attributes for the modest success (in comparison to the field of self-healing polymers, [2][3][4] self-healing composites, [5] self-healing concrete [6] ) in developing self-healing metallic materials. For a material to become self-healing local processes leading to "local In comparison to other materials, in metals and metallic systems self-healing of cracks and crack-initiating defects is difficult to achieve due to the fact the solute atoms that act as healing agents are relatively small and generally have a relatively low mobility at the prevailing operating temperatures. In this review, the scientifically most interesting and industrially most promising approaches to self-healing metals are presented and discussed. The various approaches are separated in autonomous healing methods based on an intrinsic (solid-state diffusion) mechanism and assisted healing methods that need an external intervention. Some promising routes are identified while in other cases the approach has too many intrinsic limitations. Recently, a number of computational studies using molecular dynamics and finite element modeling have been performed to analyze the self-healing potential of...

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Self‐Healing and Shape Memory Effects in Gold Microparticles through the Defects‐Mediated Diffusion

et al. 2017

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Some metal alloys subjected to irreversible plastic deformation can repair the inflicted damage and/or recover their original shape upon heating. The conventional shape memory effect in metallic alloys relies on collective, or “military” phase transformations. This work demonstrates a new and fundamentally different type of self‐healing and shape memory in single crystalline faceted nano and microparticles of pure gold, which are plastically deformed with an atomic force microscope tip. It is shown that annealing of the deformed particles at elevated temperatures leads to nearly full recovery of their initial asymmetric polyhedral shape, which does not correspond to global energy minimum shape. The atomistic molecular dynamic simulations demonstrate that the shape recovery of the particles is controlled by the self‐diffusion of gold atoms along the terrace ledges formed during the particles indentation. This ledge‐guided diffusion leads to shape recovery by the irreversible diffusion process. A semiquantitative model of healing developed in this work demonstrates a good agreement with the experimental data.

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Autonomous filling of creep cavities in Fe-Au alloys studied by synchrotron X-ray nano-tomography

Cited by 35 publications

References 43 publications

Finite element modelling of creep cavity filling by solute diffusion

Finite element modelling of creep cavity filling by solute diffusion

Self‐Healing Phenomena in Metals

Self‐Healing and Shape Memory Effects in Gold Microparticles through the Defects‐Mediated Diffusion

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