Strain gradient crystal plasticity modelling of size effects in a hierarchical martensitic steel using the Voronoi tessellation method

Sun, Fengzhen; Meade, Edward D.; O’Dowd, Noel P.

doi:10.1016/j.ijplas.2019.03.009

Cited by 58 publications

(8 citation statements)

References 74 publications

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“…Most techniques indicate the existence of a large GND density close to GBs even after a small plastic deformation. On the modeling side, such feature was reproduced by crystal plasticity calculations of polycrystalline aggregates (Berbenni et al, 2020, Cordero et al, 2012, Haouala et al, 2020, Sun et al, 2019. In a recent investigation based on Dislocation Dynamics (DD) simulations (Jiang et al, 2019), it was also shown that the dislocation storage rate dρ/dγ recorded inside grains agrees with a prediction of Ashby (Ashby, 1970), i.e., is proportional to the inverse of grain size 1/d.…”

Section: Introductionmentioning

confidence: 76%

Stress fields of finite-size dislocation walls and prediction of back stress induced by geometrically necessary dislocations at grain boundaries

Jiang¹,

Monnet²,

Devincre³

2020

Journal of the Mechanics and Physics of Solids

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At low strain, geometrically necessary dislocations (GND) confined in the close vicinity of grain boundaries can be approximated as a dislocation wall structure called a GND facet. Analytical solutions derived from Field Dislocations Mechanics (FDM) theory allow calculating the stress components associated with the GND facets but are unable to account for the stress field variation induced by finite size effect. Dislocation dynamics simulation is used to investigate the true stress field of GND facets. The geometry, dimension and dislocation density of three generic types of GND facets (twist, tilt and epitaxial facets) are systematically studied. In all cases, the stress field generated by GND facets is proportional to the surface GND density and its spatial distribution can be recovered using FDM solution combined with two scaling parameters identified from DD simulation results. This calculation procedure can be generalized to any crystal structure by relating the components of the surface Nye's tensor to the solutions of simple cubic slip systems. Finally, static and dynamic tests are made to validate the calculation of back stress within regular grains bounded by GND facets.

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Section: Introductionmentioning

confidence: 76%

Stress fields of finite-size dislocation walls and prediction of back stress induced by geometrically necessary dislocations at grain boundaries

Jiang¹,

Monnet²,

Devincre³

2020

Journal of the Mechanics and Physics of Solids

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“…Thus, the grains are essentially columnar in this direction. This approach has been previously adopted by a number of authors, such as O'Dowd and co-workers 3,4 , Dunne and co-workers 6,25 , Shollock and co-workers 26,86 etc. However, the grain size measured from 2D…”

Section: Discussionmentioning

confidence: 99%

“…Thus, the grains are essentially columnar in this direction. This approach has been previously adopted by a number of authors, such as O'Dowd et al, 3,4 et al, 26,86 etc. The grains are permitted to strain in the out-of-plane direction but must have uniform out of plane strain in the entire model.…”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…The development of computational prediction methods for microstructure-sensitive fatigue crack initiation (FCI) is an important problem that will benefit a wide range of industries, including aerospace, 1 medical device, 2 and power generation. 3,4 The critical importance of characterization of the interrelationships between manufacturing process, microstructure, material properties, and mechanical performance (structural integrity) 5,6 has been highlighted by a recent aeroengine fan hub failure investigation. 7,8 This report provides detailed proof of the serious risks associated with not considering these relationships, particularly for fatigue crack initiation in real applications, in this case, an aeroengine fan hub failure of Ti6Al4V alloy, not previously considered susceptible to facet fatigue.…”

Section: Introductionmentioning

confidence: 99%

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A high-fidelity crystal-plasticity finite element methodology for low-cycle fatigue using automatic electron backscatter diffraction scan conversion: Application to hot-rolled cobalt–chromium alloy

Leen

Harrison

2021

Proceedings of the Institution of Mechanical Engineers, Part L:

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The common approach to crystal-plasticity finite element modeling for load-bearing prediction of metallic structures involves the simulation of simplified grain morphology and substructure detail. This paper details a methodology for predicting the structure–property effect of as-manufactured microstructure, including true grain morphology and orientation, on cyclic plasticity, and fatigue crack initiation in biomedical-grade CoCr alloy. The methodology generates high-fidelity crystal-plasticity finite element models, by directly converting measured electron backscatter diffraction metal microstructure grain maps into finite element microstructural models, and thus captures essential grain definition for improved microstructure–property analyses. This electron backscatter diffraction-based method for crystal-plasticity finite element model generation is shown to give approximately 10% improved agreement for fatigue life prediction, compared with the more commonly used Voronoi tessellation method. However, the added microstructural detail available in electron backscatter diffraction–crystal-plasticity finite element did not significantly alter the bulk stress–strain response prediction, compared to Voronoi tessellation–crystal-plasticity finite element. The new electron backscatter diffraction-based method within a strain-gradient crystal-plasticity finite element model is also applied to predict measured grain size effects for cyclic plasticity and fatigue crack initiation, and shows the concentration of geometrically necessary dislocations around true grain boundaries, with smaller grain samples exhibiting higher overall geometrically necessary dislocations concentrations. In addition, minimum model sizes for Voronoi tessellation–crystal-plasticity finite element and electron backscatter diffraction–crystal-plasticity finite element models are proposed for cyclic hysteresis and fatigue crack initiation prediction.

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Novel ultra-high aluminum content eutectic high entropy alloys with duplex-reinforced phases and labyrinthine structure

et al. 2022

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Strain gradient crystal plasticity modelling of size effects in a hierarchical martensitic steel using the Voronoi tessellation method

Cited by 58 publications

References 74 publications

Stress fields of finite-size dislocation walls and prediction of back stress induced by geometrically necessary dislocations at grain boundaries

Stress fields of finite-size dislocation walls and prediction of back stress induced by geometrically necessary dislocations at grain boundaries

A high-fidelity crystal-plasticity finite element methodology for low-cycle fatigue using automatic electron backscatter diffraction scan conversion: Application to hot-rolled cobalt–chromium alloy

Novel ultra-high aluminum content eutectic high entropy alloys with duplex-reinforced phases and labyrinthine structure

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