Thermodynamic theory of crystal plasticity: Formulation and application to polycrystal fcc copper

Lieou, Charles K. C.; Bronkhorst, Curt A.

doi:10.1016/j.jmps.2020.103905

Cited by 26 publications

(8 citation statements)

References 126 publications

(193 reference statements)

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“…The elastic constants can be written as a function of absolute temperature by

[ 57 ] and shear modulus with

, where the constants,

are designated in Table 4 for Cu/Nb nano-layers.…”

Section: Resultsmentioning

confidence: 99%

“…The elastic constants can be written as a function of absolute temperature by C ij = χ ij + ω ij T [57] and shear modulus with µ = m 1 + m 2 T, where the constants, χ ij , ω ij , m 1 , m 2 are designated in Table 4 for Cu/Nb nano-layers. The effective functionals, saturation shear resistance and initial hardening, also change in terms of temperature.…”

Section: Homogenized Level Temperature Effectsmentioning

confidence: 99%

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Multi-Scale Analyses and Modeling of Metallic Nano-Layers

Moleinia

Bahr

2021

Materials

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The current work centers on multi-scale approaches to simulate and predict metallic nano-layers’ thermomechanical responses in crystal plasticity large deformation finite element platforms. The study is divided into two major scales: nano- and homogenized levels where Cu/Nb nano-layers are designated as case studies. At the nano-scale, a size-dependent constitutive model based on entropic kinetics is developed. A deep-learning adaptive boosting technique named single layer calibration is established to acquire associated constitutive parameters through a single process applicable to a broad range of setups entirely different from those of the calibration. The model is validated through experimental data with solid agreement followed by the behavioral predictions of multiple cases regarding size, loading pattern, layer type, and geometrical combination effects for which the performances are discussed. At the homogenized scale, founded on statistical analyses of microcanonical ensembles, a homogenized crystal plasticity-based constitutive model is developed with the aim of expediting while retaining the accuracy of computational processes. Accordingly, effective constitutive functionals are realized where the associated constants are obtained via metaheuristic genetic algorithms. The model is favorably verified with nano-scale data while accelerating the computational processes by several orders of magnitude. Ultimately, a temperature-dependent homogenized constitutive model is developed where the effective constitutive functionals along with the associated constants are determined. The model is validated by experimental data with which multiple demonstrations of temperature effects are assessed and analyzed.

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“…The elastic constants can be written as a function of absolute temperature by

[ 57 ] and shear modulus with

, where the constants,

are designated in Table 4 for Cu/Nb nano-layers.…”

Section: Resultsmentioning

confidence: 99%

Section: Homogenized Level Temperature Effectsmentioning

confidence: 99%

Multi-Scale Analyses and Modeling of Metallic Nano-Layers

Moleinia

Bahr

2021

Materials

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“…We do so in order to better quantify the stored energy of cold work within the context of a series of very recently published quasi-static experimental results and challenge the ideas within the theory in isotropic form. We have also recently extended the theory to crystallographic systems to represent single crystals [82].…”

Section: Introductionmentioning

confidence: 99%

Thermomechanical conversion in metals: dislocation plasticity model evaluation of the Taylor-Quinney coefficient

Lieou¹,

Bronkhorst²

2020

Preprint

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Using a partitioned-energy thermodynamic framework which assigns energy to that of atomic configurational stored energy of cold work and kineticvibrational, we derive an important constraint on the Taylor-Quinney coefficient, which quantifies the fraction of plastic work that is converted into heat during plastic deformation. Associated with the two energy contributions are two separate temperatures -the ordinary temperature for the thermal energy and the effective temperature for the configurational energy. We show that the Taylor-Quinney coefficient is a function of the thermodynamically defined effective temperature that measures the atomic configurational disorder in the material. Finite-element analysis of recently published experiments on the aluminum alloy 6016-T4 [1], using the thermodynamic dislocation theory (TDT), shows good agreement between theory and experiment for both stress-strain behavior and temporal evolution of the temperature. The simulations include both conductive and convective thermal energy loss during the experiments, and significant thermal gradients exist within the simulation results. Computed values of the differential Taylor-Quinney coefficient are also presented and suggest a value which differs between materials and increases with increasing strain.

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“…He proposed the energy and dissipation of dislocated crystals and derived the governing equations of TDT exhibiting indeed both types of work hardening. Of the various dislocation based plasticity theories, we mention here only those in [39,15,8,7,1,3,33,16,10,41,34] which are closely relevant to our thermodynamic approach.…”

Section: Introductionmentioning

confidence: 99%

Dislocation impediment by the grain boundaries in polycrystals

Piao

2020

Preprint

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Thermodynamic dislocation theory incorporating dislocation impediment by the grain boundaries is developed to analyze the shear test of polycrystals. With a small set of physics based material parameters, we are able to simulate the stress-strain curves for the load and its reversal, which are consistent with the experimental curves of Thuillier and Manach [42]. Representative distributions of plastic slip under load and its reversal are presented, and their evolution explains the extended length of the transition stage during load reversal.

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Thermodynamic theory of crystal plasticity: Formulation and application to polycrystal fcc copper

Cited by 26 publications

References 126 publications

Multi-Scale Analyses and Modeling of Metallic Nano-Layers

Multi-Scale Analyses and Modeling of Metallic Nano-Layers

Thermomechanical conversion in metals: dislocation plasticity model evaluation of the Taylor-Quinney coefficient

Dislocation impediment by the grain boundaries in polycrystals

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