Sensitivity of Ultrasonic Attenuation and Velocity Change to Cyclic Deformation in Pure Aluminum

Wang, J.; Fang, Qingming; Zhang, Zhengang

doi:10.1002/(sici)1521-396x(199809)169:1<43::aid-pssa43>3.0.co;2-8

Cited by 13 publications

(3 citation statements)

References 9 publications

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“…For instance, in Ref. 41, the authors measure the attenuation and the velocity change for longitudinal waves propagating in aluminum. Then, they solve the system of Eqs.…”

Section: A Velocity Changes and Attenuationsmentioning

confidence: 99%

Wave propagation through a random array of pinned dislocations: Velocity change and attenuation in a generalized Granato and Lücke theory

et al. 2005

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A quantitative theory of the elastic wave damping and velocity change due to interaction with dislocations is presented. It provides a firm theoretical basis and a generalization of the Granato and Lücke model ͓J. Appl. Phys. 27, 583 ͑1956͔͒. This is done considering the interaction of transverse ͑T͒ and longitudinal ͑L͒ elastic waves with an ensemble of dislocation segments randomly placed and randomly oriented in an elastic solid. In order to characterize the coherent wave propagation using multiple scattering theory, a perturbation approach is used, which is based on a wave equation that takes into account the dislocation motion when forced by an external stress. In our calculations, the effective velocities of the coherent waves appear at first order in perturbation theory while the attenuations have a part at first order due to the internal viscosity and a part at second order due to the energy that is taken away from the incident direction. This leads to a frequency dependence law for longitudinal and transverse attenuations that is a combination of quadratic and quartic terms instead of the usual quadratic term alone. Comparison with resonant ultrasound spectroscopy ͑RUS͒ and electromagnetic acoustic resonance ͑EMAR͒ experiments is proposed. The present theory explains the difference experimentally observed between longitudinal and transverse attenuations ͓Ledbetter, J. Mater. Res. 10, 1352 ͑1995͔͒.

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“…For instance, in Ref. 41, the authors measure the attenuation and the velocity change for longitudinal waves propagating in aluminum. Then, they solve the system of Eqs.…”

Section: A Velocity Changes and Attenuationsmentioning

confidence: 99%

Wave propagation through a random array of pinned dislocations: Velocity change and attenuation in a generalized Granato and Lücke theory

et al. 2005

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“…The best fit to the experimental data is obtained for p i = 0.75, q i = 1.0, anḋ ε 0i = 5.0×10 8 s −1 . The Boltzmann constant was taken to be k b = 1.38×10 −23 J/K and the magnitude of the Burgers' vector was assumed to be b = 2.86×10 −10 m [Wang et al 1998].…”

Section: 2mentioning

confidence: 99%

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2008

J. Mech. Mater. Struct.

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The mechanical threshold stress plasticity model of Follansbee and Kocks was designed to predict the flow stress of metals and alloys in the regime where thermally activated mechanisms are dominant and high temperature diffusion effects are negligible. In this paper we present a model that extends the original mechanical threshold stress to the high strain-rate regime (strain rates higher than 10 4 s −1 ) and attempts to allow for high temperature effects. We use a phonon drag model for moderate strain rates and an overdriven shock model for extremely high strain rates. A temperature dependent model for the evolution of dislocation density is also presented. In addition, we present a thermodynamically-based model for the evolution of temperature with plastic strain. Parameters for 6061-T6 aluminum alloy are determined and compared with experimental data. The strain-rate dependence of the flow stress of 6061-T6 aluminum is found to be in excellent agreement with experimental data. The amount of thermal softening is underestimated at high temperatures (greater than 500 K) but still is an improvement over the original model. We also find that the pressure dependence of the shear modulus does not completely explain the pressure dependence of the flow stress of 6061-T6 aluminum alloy.

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“…[75], Oka F. [76], Pezzyna P. [6], Placidi L. [77,78], Sidoroff F [79]., Twerdaard V. [75], Wang J. [65,80] и другие. С применением современных средств неразрушающего контроля и диагностики, а именно с использованием результатов мониторинга состояния материала, может быть достигнуто более высокое качество (уточнённые результаты) оценки степени повреждения конструкций и механизмов машин.…”

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