Finite element modelling of creep cavity filling by solute diffusion

Versteylen, C. D.; Szymanski, Nikodem; Sluiter, Marcel H. F.; Dijk, Niels van

doi:10.1080/14786435.2017.1418097

Cited by 12 publications

(18 citation statements)

References 27 publications

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“…The surface precipitation of the solutes can be simplified into a 1D diffusion process, where the solute agents diffuse towards the free surface, and after reaching the surface they nucleate to form precipitates. The 1D flux and the equivalent thickness of the precipitation layer are estimated by [23]:…”

Section: The Evolution Of the Equivalent Thickness Of The Grain-intermentioning

confidence: 99%

Surface precipitation of supersaturated solutes in a ternary Fe–Au–W alloy and its binary counterparts

Kwakernaak

Brouwer

et al. 2020

J Mater Sci

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The precipitation of supersaturated solutes at free surfaces in ternary Fe–3Au–4W and binary Fe–3Au and Fe–4W alloys (composition in weight percentage) for different ageing times was investigated at a temperature of 700 °C. The time evolution of the surface precipitation is compared among the three alloys to investigate the interplay between the Au and W solutes in the ternary system. The Au-rich grain-interior surface precipitates show a similar size and kinetics in the Fe–Au–W and Fe–Au alloys, while the W-rich grain-interior surface precipitates show a smaller size and a higher number density in the Fe–Au–W alloy compared to the Fe–W alloy. The kinetics of the precipitation on the external free surface for the ternary Fe–Au–W alloy is compared to the previously studied precipitation on the internal surfaces of the grain-boundary cavities during creep loading of the same alloy. Graphical abstract

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Section: The Evolution Of the Equivalent Thickness Of The Grain-intermentioning

confidence: 99%

Surface precipitation of supersaturated solutes in a ternary Fe–Au–W alloy and its binary counterparts

Kwakernaak

Brouwer

et al. 2020

J Mater Sci

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“…Aaron and Aaronson [38] found that the time exponent for the volumetric growth of precipitates at grain boundaries is between 0.66 and 1 with an average of 0.81. A recent study by Versteylen and coworkers [39] showed that the time exponent for the filling of a grain-boundary cavity by diffusional precipitation ranges from 0.5 to 1. The actual value depends on (i) the ratio between the cavity spacing and the cavity radius and (ii) the ratio between the grain-boundary diffusivity and bulk diffusivity of the supersaturated solute atoms.…”

Section: Nucleation and Growth Of Creep Cavities And Precipitatesmentioning

confidence: 99%

Self healing of creep damage in iron-based alloys by supersaturated tungsten

et al. 2019

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When metals are mechanically loaded at elevated temperatures for extended periods of time, creep damage will occur in the form of cavities at grain boundaries. In the present experiments it is demonstrated that in binary iron-tungsten alloys creep damage can be self healed by selective precipitation of a W-rich phase inside these cavities. Using synchrotron X-ray nano-tomography the simultaneous evolution of creep cavitation and precipitation is visualized in 3D images with a resolution down to 30 nm. The degree of filling by precipitation is analysed for a large collection of individual creep cavities. Two clearly different types of behaviour are observed for isolated and linked cavities, where the isolated cavities can be filled completely, while the linked cavities continue to grow. The demonstrated selfhealing potential of tungsten in iron-based metal alloys provides a new perspective on the role of W in high-temperature creep-resistant steels.

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“…Modeling studies on (intrinsic) self‐healing of structural damage in metals have up to recently been small in number. Computational investigations generally either focus on microscopic cracks using continuum models by employing finite element model (FEM) calculations or on the time evolution of nanoscale cuts or voids using atomistic models by employing molecular dynamics (MD) calculations . In some cases multiscale modeling is used to incorporate atomistic properties in the microscopic description of the damage repair …”

Section: Modelingmentioning

confidence: 99%

“…The time required to fill a creep cavity by BN precipitation was analyzed as a function of the creep cavity size, the applied stress and the aspect ratio of the cavity. The diffusional flux of supersaturated solute responsible for the filling of creep cavities in the self‐healing process was analyzed by Versteylen et al for bcc Fe alloys by FEM modeling of creep cavities located on a grain boundary. It was found that the effective dimensionality of the solute flux strongly depends on the spacing of the creep cavities with respect to the cavity size and on the ratio between the grain‐boundary diffusivity and the bulk diffusivity.…”

Section: Modelingmentioning

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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Finite element modelling of creep cavity filling by solute diffusion

Cited by 12 publications

References 27 publications

Surface precipitation of supersaturated solutes in a ternary Fe–Au–W alloy and its binary counterparts

Surface precipitation of supersaturated solutes in a ternary Fe–Au–W alloy and its binary counterparts

Self healing of creep damage in iron-based alloys by supersaturated tungsten

Self‐Healing Phenomena in Metals

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