Temperature dependence of dynamic deformation in FCC metals, aluminum and invar

Chen, Laura; Swift, Damian; Austin, Ryan; Florando, J.N.; Hawreliak, J.; Lazicki, Amy; Saculla, M. D.; Eakins, Daniel E.; Kumar, M. Arul

doi:10.1063/1.4971671

Cited by 6 publications

(2 citation statements)

References 41 publications

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“…The transition is shown in Figure 2, that shows a sketch of the flow stress as a function of rate for two different temperatures as specimens enter a phonon limited regime. Such an inversion has been observed both in Hugoniot elastic limit measurements (Chen et al, 2017;Gurrutxaga-Lerma et al, 2017;Kanel, 2014;Zaretsky and Kanel, 2013) across a wide range of temperatures, and in shear-pressure experiments (Grunschel et al, 2012) close to melt. These experiments have provided some confidence in phonon drag mechanisms being active at high rates, with some quantitative discrepancies, proposed by Grunschel et al (2012) to be due to interactions between moving dislocations.…”

Section: Introductionmentioning

confidence: 70%

“…Despite the widespread use of the uniaxial stress geometry for model parametrisation, exemplified in data collation by Liang and Khan (1999), Jordan et al (2013) and Hansen et al (2013) measurements at elevated temperatures and rates above 10 4 s −1 are sparse. The majority of measurements in that temperature and rate regime exist under conditions of shear strain Grunschel and Clifton, 2007) or the uni-axial strain conditions present in shock wave propagation (Chen et al, 2017;Gurrutxaga-Lerma et al, 2017;Kanel, 2014). Furthermore, in both cases measurements typically begin an order of magnitude above the transition rate.…”

Section: Introductionmentioning

confidence: 99%

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Characterisation of high rate plasticity in the uniaxial deformation of high purity copper at elevated temperatures

Lea

Jardine

2018

International Journal of Plasticity

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In uni-axial compression at strain rates above 10 4 s −1 , FCC metals exhibit a rapid increase in strength. Mechanisms proposed to be responsible for this transition can be broadly split into two categories; that mobile dislocation velocities become limited by quasi-viscous scattering from phonons, or that some change occurs in the evolution of the materials dislocation structure. The relative contribution of each mechanism is difficult to identify, in part due to a scarcity of experimental measurements in varying deformation conditions. In this paper, we perform uni-axial compression experiments that reach rates between 10 4 and 10 5 s −1 , at temperatures between 300 and 600K. Analysis of the data at 0.1 strain shows both the absolute and relative levels of thermal softening increase with strain rate, an anomalous result in comparison to both existing models and measurements below the transition.

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Section: Introductionmentioning

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Characterisation of high rate plasticity in the uniaxial deformation of high purity copper at elevated temperatures

Lea

Jardine

2018

International Journal of Plasticity

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Elastic precursor wave decay in shock-compressed aluminum over a wide range of temperature

Austin

2018

Journal of Applied Physics

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The effect of temperature on the dynamic flow behavior of aluminum is considered in the context of precursor wave decay measurements and simulations. In this regard, a dislocation-based model of high-rate metal plasticity is brought into agreement with previous measurements of evolving wave profiles at 300 to 933 K, wherein the amplification of the precursor structure with temperature arises naturally from the dislocation mechanics treatment. The model suggests that the kinetics of inelastic flow and stress relaxation are governed primarily by phonon scattering and radiative damping (sound wave emission from dislocation cores), both of which intensify with temperature. The manifestation of these drag effects is linked to low dislocation density ahead of the precursor wave and the high mobility of dislocations in the face-centered cubic lattice. Simulations performed using other typical models of shock wave plasticity do not reproduce the observed temperature-dependence of elastic/plastic wave structure.

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Evolution of shock compression pulses in polymethylmethacrylate and aluminum

Popova

Mayer

Khishchenko

2018

Journal of Applied Physics

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The numerical study of the dynamics of shock compression pulses in polymethylmethacrylate (PMMA) and aluminum is performed in both viscoelastic and hydrodynamic approximations. The Maxwell relaxation model with two parameters, the relaxation time and the static yield strength, is used for both materials for a description of their viscoelastic properties. Constant values of the parameters suffice for a description of shock-wave profiles in the case of PMMA, while changes of these parameters in the course of deformation are needed to be taken into account in the case of aluminum. A method of accounting of such changes is proposed based on the kinetic equations for mobile and immobilized dislocations. The proposed approach lets us take into account the main features of the elastic precursor in aluminum, as well as its change with distance and target temperature. The approach by its complexity and accuracy lies between the simple relaxation models and the complete dislocation-based ones. Using the proposed models, we investigate the influence of stress deviators on the change of compression-pulse amplitude with the propagation distance inside the material. The shock pulse in the viscoelastic approximation has greater amplitude in comparison with the hydrodynamic one for low distances due to higher stiffness and conversely at larger distances due to the greater velocity of propagation of the unloading wave that overtakes the shock wave front. The maximum difference between two approximations in the value of the shock pulse amplitude is about 35% for PMMA and about 90% for aluminum.

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Temperature dependence of dynamic deformation in FCC metals, aluminum and invar

Abstract: Effect of temperature, strain, and strain rate on the flow stress of aluminum under shockwave compression Journal of Applied Physics 112, 073504 (2012);

Cited by 6 publications

References 41 publications

Characterisation of high rate plasticity in the uniaxial deformation of high purity copper at elevated temperatures

Characterisation of high rate plasticity in the uniaxial deformation of high purity copper at elevated temperatures

Elastic precursor wave decay in shock-compressed aluminum over a wide range of temperature

Evolution of shock compression pulses in polymethylmethacrylate and aluminum

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