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

Zhang, Ping; Zhang, Lu; Baxevanakis, Konstantinos P.; Lu, Shiqi; Zhao, Liguo; Bullough, Chris

doi:10.1016/j.ijfatigue.2020.106095

Cited by 20 publications

(4 citation statements)

References 71 publications

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“…In this sense, a crystallographic structure is of major importance for the plasticity and plastic deformation of metallic materials. Plastic deformation is realized by dislocation movement, where slipping is the main mechanism carried out in a certain slipping system, which is defined by the family of crystallographic planes and the corresponding crystallographic direction [29]. It is known that five independent slip systems are required for deforming metal and alloys plastically without the formation of cracks, fractures, etc.…”

Section: Discussionmentioning

confidence: 99%

Effect of Electron Beam Surface Modification on the Plasticity of Inconel Alloy 625

Valkov,

Kotlarski,

Parshorov

et al. 2024

Coatings

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In the present work, we present results on the influence of electron beam surface modification on the resistance to plastic deformation and plasticity of Inconel alloy 625. During the treatment procedure, the electron beam currents were 10 and 20 mA, corresponding to beam powers of 600 W and 1200 W. The structures of the modified specimens were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The nanohardness and Young’s modulus were studied through nanoindentation experiments. The plasticity of the treated materials as well as of the untreated ones was studied through an evaluation of H3/E2, which points to resistance to plastic deformation. The results obtained show that the electron beam surface modification procedure leads to a reorientation of microvolumes and the formation of a preferred crystallographic orientation. The surface treatment of the samples using an electron beam with a power of 600 W did not lead to major changes in the structures of the samples. However, the use of a beam with a power of 1200 W led to the formation of a clearly separated modified zone with a thickness in the range of 13 to 15 μm. The Young’s modulus increased from about 100 to 153 GPa in the case of electron beam surface modification using the lower-power electron beam. The application of the higher-power electron beam did not lead to a significant change in the modulus of elasticity as compared to the untreated specimen. Also, it was found that the treatment procedure pointed to a decrease in nanohardness when the maximum power of the electron beam was applied. The resistance to plastic deformation, i.e., the H3/E2 ratio, showed that the ratio decreased significantly in both cases of electron beam surface modification, pointing to an improvement in the plasticity of the surface of the Inconel alloy 625.

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Section: Discussionmentioning

confidence: 99%

Effect of Electron Beam Surface Modification on the Plasticity of Inconel Alloy 625

Valkov,

Kotlarski,

Parshorov

et al. 2024

Coatings

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“…The kinematic hardening is mainly used to account for the asymmetric yielding behavior of the materials observed upon loading and unloading. 15,49,50 It is worth noting that in this experiment, the asymmetric yield behavior of the material can be ignored, as shown in Figure 9. Therefore, this manuscript did not consider kinematic hardening in the crystal plasticity model.…”

Section: Crystal Plasticity Modeling and Parameter Calibrationmentioning

confidence: 99%

“…The isotropic hardening rule used to determine the change in material strength is given by the following expression:

({, \begin{array}{c} {\overset{τ}{true}}_{c}^{α} goodbreak= \sum_{r = 1}^{N_{a}} h_{αβ} (||, {\overset{γ}{true}}^{α}) \\ \begin{matrix} left \\ h_{italicαβ} = h_{r} (q_{italicsl} + (1 - q_{italicsl}) δ_{italicαr}) \\ h_{r} = h_{0} {sech}^{2} |\frac{h_{0} γ^{α}}{τ_{s} - τ_{0}}| \end{matrix} \end{array})

where

h_{αβ}

is the slip hardening modulus;

q_{sl}

is the ratio of latent to self‐hardening;

δ_{αr}

is the Kronecker delta;

h_{r}

is the potential hardening modulus of the material;

h_{0}

is the initial hardening modulus;

τ_{s}

is the saturation stress; and

τ_{0}

is the initial critical resolved shear stress. The kinematic hardening is mainly used to account for the asymmetric yielding behavior of the materials observed upon loading and unloading 15,49,50 . It is worth noting that in this experiment, the asymmetric yield behavior of the material can be ignored, as shown in Figure 9.…”

Section: Microstructure Modeling Including Surface Integrity Characte...mentioning

confidence: 99%

A crystal plastic finite element model for the effect of surface integrity on multiaxial fatigue life after multistage machining processes

Liang,

Jiao,

Yan

et al. 2024

Fatigue Fract Eng Mat Struct

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Surface integrity influences the material fatigue performance significantly, but most micromechanical models based on crystal plasticity only consider the microstructure of the matrix. In this paper, a crystal plastic finite element modeling method was proposed, which simultaneously considered surface roughness, residual stress, and gradual microstructure. It was verified through multiaxial fatigue experiments of materials processed by different multistage machining processes. The results show that larger axial residual compressive stress and smaller grain size can lead to higher multiaxial fatigue life. The existence of residual compressive stress causes the location of material crack initiation to decrease from the surface layer to the subsurface layer. The proposed model can predict the multiaxial fatigue life of materials within a 50% error band.

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“…Crystal plasticity (CP) constitutive models are often used to examine the correlation between mesoscopic and macroscopic mechanical responses, with a focus on the dislocation and slip properties of metallic materials. Zhang et al [12,13] developed a calculation method that combines crystal plasticity and an expansion finite element method for the purpose of predicting the growth of slip-controlled short cracks in single-crystal nickel-based superalloys. The occurrence of fracture is influenced by the cumulative shear strain of a single slip system, with the direction of crack propagation aligning with the slip surface.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of the Residual Stress at the Interface between Thermal Barrier Coating and Nickel-Based Single-Crystal Superalloy Based on Crystal Plasticity Theory

Liu,

Wang,

Yang

et al. 2023

Coatings

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Residual stress plays an important role in the formation and growth of cracks in thermal barrier coatings and single-crystal superalloy substrates. In this study, a finite element model for a planar double-layer thermal barrier coating and a crystal plasticity finite element model based on dislocation slip-induced plastic deformation of single-crystal materials were established to analyze the residual stress in the coatings and the substrate, considering the creep and crystal plasticity of the substrate materials. The simulation results show that the thermal barrier coatings bear most of the stress generated by high temperatures, and the residual stress of the substrate is small. By comparing the two material properties to calculate the interface stress when the amplitude of the interface between the substrate and the coating is 30 μm and the thickness of the thermal grown oxide layer is 5 µm, the interfacial stress of the substrate at the macro scale was found to be similar to the interfacial stress at the micro slip system scale. Based on the cumulative shear strain, it was determined that the [001]-, [011]-, and [111]-oriented alloys activated the 12, 8, and 4 groups, respectively, under the combined action of thermal stress and centrifugal force of the coating. Comparing the activation of different initial orientation slip systems and the magnitude of the yield stress provides a theoretical foundation to study the structural integrity of single-crystal alloys.

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

Cited by 20 publications

References 71 publications

Effect of Electron Beam Surface Modification on the Plasticity of Inconel Alloy 625

Effect of Electron Beam Surface Modification on the Plasticity of Inconel Alloy 625

A crystal plastic finite element model for the effect of surface integrity on multiaxial fatigue life after multistage machining processes

Numerical Simulation of the Residual Stress at the Interface between Thermal Barrier Coating and Nickel-Based Single-Crystal Superalloy Based on Crystal Plasticity Theory

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