3D DDD modelling of dislocation–precipitate interaction in a nickel-based single crystal superalloy under cyclic deformation

Lin, Bing; Huang, Minsheng; Zhao, Liguo; Roy, Anish; Silberschmidt, Vadim V.; Barnard, Nicholas; Whittaker, Mark; McColvin, G.

doi:10.1080/14786435.2018.1447159

Cited by 12 publications

(2 citation statements)

References 49 publications

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“…By explicitly modelling behaviours of individual dislocations along defined slip planes, the discrete structure of slip bands can be obtained [20,21]. Although DDP or Discrete Dislocation Dynamics (DDD) modelling has been used to study crystallographic slip, these methods are time-consuming and limited to an extremely small scale and volume (a few microns) [22,23].…”

Section: Introductionmentioning

confidence: 99%

Discrete crystal plasticity modelling of slip-controlled cyclic deformation and short crack growth under low cycle fatigue

Zhang

Baxevanakis

et al. 2021

International Journal of Fatigue

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Section: Introductionmentioning

confidence: 99%

Discrete crystal plasticity modelling of slip-controlled cyclic deformation and short crack growth under low cycle fatigue

Zhang

Baxevanakis

et al. 2021

International Journal of Fatigue

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“…Discrete Dislocation Dynamics (DDD) simulations have been employed extensively in the literature to shed light on the mechanisms of interaction between a/2 110 {111} dislocations and γ precipitates (Mohles, 2004;Rao et al, 2004;Yashiro et al, 2006;Vattré et al, 2009;Queyreau et al, 2010;Huang et al, 2012;Hafez Haghighat et al, 2013;Li and Wang, 2014;Hussein et al, 2017;Lin et al, 2018;Ali et al, 2020). However, the hybrid mechanism described above was not reported in these studies, despite its strong, albeit indirect, experimental evidence.…”

Section: Introductionmentioning

confidence: 99%

A discrete dislocation dynamics study of precipitate bypass mechanisms in nickel-based superalloys

Chatterjee,

Li,

2021

Preprint

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Order strengthening in nickel-based superalloys is associated with the extra stress required for dislocations to bypass the γ precipitates distributed in the γ matrix. Depending on the operating conditions and microstructure, a rich variety of bypass mechanism has been identified, with various shearing and Orowan looping processes gradually giving way to climb bypass as the operating conditions change from the low/intermediate temperatures and high stress regime, to the high temperature and low stress regime. When anti phase boundary (APB) shearing and Orowan looping mechanisms operate, the classical picture is that, at for a given volume fraction, the bypass mechanism changes from shearing to looping with increased particle size and within a broad coexistence size window. Another possibility, which is supported by indirect experimental evidence, is that a third "hybrid" transition mechanism may operate. In this paper we use discrete dislocation dynamics (DDD) simulations to study dislocation bypass mechanisms in Ni-based superalloys. We develop a new method to compute generalized stacking fault forces in DDD simulations, based on a concept borrowed from complex analysis and known as the winding number of a closed curve about a point. We use this method to study the mechanisms of bypass of a square lattice of spherical γ precipitates by a/2 110 {111} edge dislocations, as a function of the precipitates volume fraction and size. We show that not only the hybrid mechanism is possible, but also that it is operates as a transition mechanism between the shearing and looping regimes over a large range of precipitates volume fraction and radii. Based on our simulation results, we propose a simple model for the strength of this mechanism. We also consider the effects of a γ/γ lattice misfit on the bypass mechanisms, which we approximate by an additional precipitate stress computed according to Eshelby's inclusion theory. We show that in the shearing and hybrid looping-shearing regimes, a lattice misfit generally results in an increased bypass stress. For sufficiently high lattice misfit, the critical bypass configuration in attractive dislocation-precipitates interactions changes dramatically, and the bypass stress is controlled by the pinning of the trailing dislocation on the exit side of the precipitates, similar to what has been proposed in the high-temperature creep literature.

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Molecular dynamics study of fatigue mechanical properties and microstructural evolution of Ni-based single crystal superalloys under cyclic loading

Chen

et al. 2020

Computational Materials Science

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3D DDD modelling of dislocation–precipitate interaction in a nickel-based single crystal superalloy under cyclic deformation

Cited by 12 publications

References 49 publications

Discrete crystal plasticity modelling of slip-controlled cyclic deformation and short crack growth under low cycle fatigue

Discrete crystal plasticity modelling of slip-controlled cyclic deformation and short crack growth under low cycle fatigue

A discrete dislocation dynamics study of precipitate bypass mechanisms in nickel-based superalloys

Molecular dynamics study of fatigue mechanical properties and microstructural evolution of Ni-based single crystal superalloys under cyclic loading

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