A micromechanical image-based model for the featureless zone of a Fe–Ni dissimilar weld

Barrera, Olga; Tarleton, Edmund

doi:10.1080/14786435.2014.886023

Cited by 13 publications

(14 citation statements)

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“…These methods involve bombarding a sample with a probe beam at MeV energy ranges, in order to create a nuclear reaction with specific target species within the host matrix. Common reactions include the 3 Heðd; pÞ 4 He reaction (7), as well as the (resonance) reaction (8).…”

Section: Experimental Techniques To Detect Hydrogen In Metalsmentioning

confidence: 99%

“…However, this has not been proven experimentally. Recently, a model, based on a classical continuum mechanics formalism, which takes into account the synergetic effect of two of the hydrogen mechanisms: HID and HELP (described in "Hydrogen-enhanced localised plasticity" section) has been proposed [7, 8]. Recent evidence from continuum modelling of the coupling between hydrogen diffusion and the mechanical behaviour of metals show that in order to observe embrittlement the HELP mechanism needs to be accompanied by another mechanism such as HID [9].…”

Section: Description Of the Failure Mechanisms Affecting Steelsmentioning

confidence: 99%

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Understanding and mitigating hydrogen embrittlement of steels: a review of experimental, modelling and design progress from atomistic to continuum

et al. 2018

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Hydrogen embrittlement is a complex phenomenon, involving several lengthand timescales, that affects a large class of metals. It can significantly reduce the ductility and load-bearing capacity and cause cracking and catastrophic brittle failures at stresses below the yield stress of susceptible materials. Despite a large research effort in attempting to understand the mechanisms of failure and in developing potential mitigating solutions, hydrogen embrittlement mechanisms are still not completely understood. There are controversial opinions in the literature regarding the underlying mechanisms and related experimental evidence supporting each of these theories. The aim of this paper is to provide a detailed review up to the current state of the art on the effect of hydrogen on the degradation of metals, with a particular focus on steels. Here, we describe the effect of hydrogen in steels from the atomistic to the continuum scale by reporting theoretical evidence supported by quantum calculation and modern experimental characterisation methods, macroscopic effects that influence the mechanical properties of steels and established damaging mechanisms for the embrittlement of steels. Furthermore, we give an insight into current approaches and new mitigation strategies used to design new steels resistant to hydrogen embrittlement.

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Section: Experimental Techniques To Detect Hydrogen In Metalsmentioning

confidence: 99%

Section: Description Of the Failure Mechanisms Affecting Steelsmentioning

confidence: 99%

Understanding and mitigating hydrogen embrittlement of steels: a review of experimental, modelling and design progress from atomistic to continuum

et al. 2018

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“…The second problem is a micromechanical investigation of hydrogen-enhanced decohesion (HEDE) in a dissimilar metal weld. More specifically, we consider the failure in the presence of hydrogen of the carbide-matrix interfaces around fine M 7 C 3 precipitates generated adjacent to the interface of an 8630 steel/IN625 nickel alloy dissimilar weld, which has been analysed extensively by Barrera et al [33]. Fig.…”

Section: Numerical Examplesmentioning

confidence: 99%

“…In this example, we investigate hydrogen enhanced decohesion (HEDE) in an AISI8630/IN625 dissimilar weld system. (A comprehensive investigations of this system is provided in Barrera et al [33].) In particular, we are interested in studying the decohesion process that takes place around fine M 7 C 3 carbide particles in a 'featureless' zone located on the Nickel side of the interface in the presence of hydrogen.…”

Section: Analysis Of Hydrogen Enhanced Decohesion (Hede) In a Dissimimentioning

confidence: 99%

“…In particular, we are interested in studying the decohesion process that takes place around fine M 7 C 3 carbide particles in a 'featureless' zone located on the Nickel side of the interface in the presence of hydrogen. Barrera et al [33] report analyses of this system using TEM imagery and used a mesh generation scheme that converted these images into a finite element mesh [40]. Their simulations have shown ; iii the hydrogen concentration in the latticeC L ; and iv the hydrogen concentration in the dislocation trapC D at the bulk material adjacent to the interface at different instants, i.e.…”

Section: Analysis Of Hydrogen Enhanced Decohesion (Hede) In a Dissimimentioning

confidence: 99%

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A modelling framework for coupled hydrogen diffusion and mechanical behaviour of engineering components

Elmukashfi

Tarleton

2020

Comput Mech

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In this paper, we propose a finite element formulation for solving coupled mechanical/diffusion problems. In particular, we study hydrogen diffusion in metals and its impact on their mechanical behaviour (i.e. hydrogen embrittlement). The formulation can be used to model hydrogen diffusion through a material and its accumulation within different microstructural features of the material (dislocations, precipitates, interfaces, etc.). Further, the effect of hydrogen on the plastic response and cohesive strength of different interfaces can be incorporated. The formulation adopts a standard Galerkin method in the discretisation of both the diffusion and mechanical equilibrium equations. Thus, a displacement-based finite element formulation with chemical potential as an additional degree of freedom, rather than the concentration, is employed. Consequently, the diffusion equation can be expressed fundamentally in terms of the gradient in chemical potential, which reduces the continuity requirements on the shape functions to zero degree, C 0 , i.e. linear functions, compared to the C 1 continuity condition required when concentration is adopted. Additionally, a consistent interface element formulation can be achieved due to the continuity of the chemical potential across the interface-concentration can be discontinuous at an interface which can lead to numerical problems. As a result, the coding of the FE equations is more straightforward. The details of the physical problem, the finite element formulation and constitutive models are initially discussed. Numerical results for various example problems are then presented, in which the efficiency and accuracy of the proposed formulation are explored and a comparison with the concentration-based formulations is presented. Keywords Hydrogen embrittlement (HE) • Hydrogen enhanced local plasticity (HELP) • Hydrogen enhanced decohesion (HEDE) • Chemical potential • Galerkin method • Interface/cohesive model Nomenclature HEDE Hydrogen enhanced decohesion HELP Hydrogen enhanced local plasticity HE Hydrogen embrittlement HID Hydrogen induced decohesion α Number of trapping sites in a trap β L Number of interstitial sites per solvent atom B Elsiddig Elmukashfi

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A unified modelling and simulation for coupled anomalous transport in porous media and its finite element implementation

Barrera

2021

Comput Mech

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This paper presents an unified mathematical and computational framework for mechanics-coupled “anomalous” transport phenomena in porous media. The anomalous diffusion is mainly due to variable fluid flow rates caused by spatially and temporally varying permeability. This type of behaviour is described by a fractional pore pressure diffusion equation. The diffusion transient phenomena is significantly affected by the order of the fractional operators. In order to solve 3D consolidation problems of large scale structures, the fractional pore pressure diffusion equation is implemented in a finite element framework adopting the discretised formulation of fractional derivatives given by Grunwald–Letnikov (GL). Here the fractional pore pressure diffusion equation is implemented in the commercial software Abaqus through an open-source UMATHT subroutine. The similarity between pore pressure, heat and hydrogen transport is also discussed in order to show that it is possible to use the coupled thermal-stress analysis to solve fractional consolidation problems.

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A micromechanical image-based model for the featureless zone of a Fe–Ni dissimilar weld

Cited by 13 publications

References 10 publications

Understanding and mitigating hydrogen embrittlement of steels: a review of experimental, modelling and design progress from atomistic to continuum

Understanding and mitigating hydrogen embrittlement of steels: a review of experimental, modelling and design progress from atomistic to continuum

A modelling framework for coupled hydrogen diffusion and mechanical behaviour of engineering components

A unified modelling and simulation for coupled anomalous transport in porous media and its finite element implementation

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