Dislocation mediated plastic flow in aluminum: Comparison between theory and experiment

Le, Khanh Chau; Tran, Tuan Minh

doi:10.1016/j.ijengsci.2017.05.005

Cited by 21 publications

(12 citation statements)

References 8 publications

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“…The composition of the aluminum alloy 6016-T4 is detailed in Table 1. It is similar enough to commercial-purity aluminum whose TDT parameters can be found in the literature [84,85]. We expect that TDT material parameters for the aluminum alloy 6016-T4 should be fairly similar to those for commercially-pure aluminum.…”

Section: Analysis Of Experiments On An Aluminum Alloysupporting

confidence: 52%

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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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Section: Analysis Of Experiments On An Aluminum Alloysupporting

confidence: 52%

“…This is the usual form of the effective-temperature evolution equation in much of the literature [83,71,72,84,85,76,77]. In other words, the usual effective-temperature evolution equation is equivalent to the statement that β = β 1 = χ/χ ss .…”

Section: Thermodynamic Framework: Derivation Of the Taylor-quinney Co...mentioning

confidence: 99%

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

Lieou¹,

Bronkhorst²

2020

Preprint

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“…To counter these difficulties, we have resorted to the large-scale leastsquares analyses that we have used in [5,6,26]. That is, we have solved the discretized system of ordinary differential-algebraic equations (DAE) numerically, provided a set of material parameters and initial values is known.…”

Section: Discretization and Methods Of Solutionmentioning

confidence: 99%

Thermodynamic dislocation theory: Size effect in torsion

Piao

2019

International Journal of Plasticity

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The thermodynamic dislocation theory developed for non-uniform plastic deformations is used here for the analysis of twisted copper wires. With a small set of physical parameters that we expect to be independent of strain rate and temperature, we can simulate the torque-twist curves that match the experimental ones of Liu et al. (2012). It is shown that the size effect results from the accumulation and pile-up of excess dislocations.

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“…We take K 1 (θ) = K 0 [1 + c 1 T P (θ − θ 0 )] with K 0 and c 1 being constant parameters, and µ(θ) = 28.8 − [ 3.44 exp(T1/T P θ)−1 ] in the unit GPa. Utilizing the least squares numerical method introduced in [6] with the experimental data in [7], we identified the basic parameters: T P = 23628 K, s = 0.52, χ 0 = 0.2489, K ρ = 10.16, K χ = 327.72, K 0 = 0.152, c 1 = 0.0057, K 2 = 1.762 × 10 −14 and the initial values presented in Table 1. With the identified parameters we simulated the torque-twist curves for bars made of aluminum alloy 5252 undergoing torsional deformations at five different twist rates, for ambient temperature T 0 = 773 K, and compared with the experimental data (see Fig.…”

Section: Methods Of Solution and Resultsmentioning

confidence: 99%