Dynamics of serrated flow in a bulk metallic glass

Ren, Jingli; Chen, C.; Wang, G.; Mattern, N.; Eckert, J.

doi:10.1063/1.3643218

Cited by 66 publications

(52 citation statements)

References 26 publications

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“…11 Moreover, direct observation of the elastic energy relaxation during serration is impossible. Since the amplitude of stress undulation during serration events initially appears to be irregularly and stochastically distributed across the variant strain conditions produced by different loading rates and temperatures, 13,17 mechanistic trends are identified in these distributions by applying dynamic and statistical analyses. Using these methods, a better understanding of the mechanism is achieved despite the characteristic lack of periodicity in intermittent serrated flow behaviour.…”

Section: Dynamics Transition At Low Temperaturementioning

confidence: 99%

Temperature dependent dynamics transition of intermittent plastic flow in a metallic glass. II. Dynamics analysis

Liu

Wang

Chan

et al. 2013

Journal of Applied Physics

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By reducing the testing temperatures down to the temperature well below the glassy transition temperature, the serrated flow behaviour during plastic deformation of a Zr-based metallic glass was experimentally investigated and the results were presented in Part I of the present paper. It shows that the yield strength, the plastic deformation ability, the density of shear bands of the metallic glass increase with decreasing temperature. In order to understand the mechanisms for the changes of the mechanical behaviour at low temperatures, in Part II of this study, the stress-time sequence in the plastic strain regime is characterized by a comprehensive dynamical and statistical analysis. The stress-time sequence is found to exhibit a chaotic state at high temperatures (>203 K), whereas a self-organized critical state is obtained at low temperatures ( 203 K) due to the freezing effect. The reasons for the transition between these two distinct spatio-temporal dynamical states are elucidated by investigating the effect of temperature on the deformation units (shear transformation zones) and the elastic interactions between neighbouring shear bands. The results demonstrate that the low temperatures results in an enhancement of the interactions between the elastic strain fields initiated by neighbouring shear bands, which is primarily responsible for the enhanced plasticity of the metallic glass and a dynamics transition. V C 2013 AIP Publishing LLC.

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Section: Dynamics Transition At Low Temperaturementioning

confidence: 99%

Temperature dependent dynamics transition of intermittent plastic flow in a metallic glass. II. Dynamics analysis

Liu

Wang

Chan

et al. 2013

Journal of Applied Physics

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“…The rising time at different strain rates covers a large time range because of different amplitudes of serration events, and the relaxation time roughly keeps constant. It is reported that with increasing strain rates from 10 −5 s −1 to 10 −2 s −1 , the loading time is several times the relaxation time, i.e., the rising time is far longer than the decreasing time, and even the maximum loading time and the relaxation time decrease four orders [37]. In addition, to explore the plastic deformation mechanisms for amorphous alloys at different strain rates, the time series analysis is helpful when a scalar time series is suspected to be a projection from a higher-dimensional dynamics, and a positive exponent is taken to be a signature of the underlying chaotic dynamics [38].…”

Section: Resultsmentioning

confidence: 99%

Serration Behavior in Pd77.5Cu6Si16.5 Alloy

Zhong¹,

Li²,

Yuan³

et al. 2016

Metals

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Abstract:The strain-rate-dependent plasticity under uniaxial compression at the strain rates of 2 × 10 −3 , 2 × 10 −4 and 2 × 10 −5 s −1 in a Pd 77.5 Cu 6 Si 16.5 alloy is investigated. At different strain rates, the serration events exhibit different amplitudes and time scales. The intersection effects take place obviously, and the loading time is much longer than the relaxation time in the serration event at three strain rates. However, the time intervals between two neighboring serrations lack any time scale, and the elastic energy density displays a power-law distribution at the strain rate of 2 × 10 −3 s −1 , which means that the self-organized critical (SOC) behavior emerges with increasing strain rates.

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“…where ∆σ and ∆ε are the elastic stress and strain in one serration event [28], as shown in Figure 1b. A normalization of the elastic energy density is applied to eliminate the statistical error, since the plastic strain causes a drift of the elastic energy density values [23].…”

Section: Resultsmentioning

confidence: 99%

“…If given a strain value, it is obtained a function value of elastic energy density by the fitting function f(ε). Figure 3b,d are frequency distribution histograms, which display the N(s) versus S, where N(s) is the number of S. The stress drop generates shear bands, following a fractal structure [29], characteristic of a power-law relation, which indicates that shear banding may self-organize to a critical state, i.e., the SOC behavior occurs [20,28]. From Figure 3b, it is obvious that the number of S reveals an increasing and then decreasing trends, which is similar to a normal distribution.…”

Section: Resultsmentioning

confidence: 99%

The Self-Organized Critical Behavior in Pd-based Bulk Metallic Glass

Zhong

Zhang

et al. 2015

Metals

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Bulk metallic glasses (BMGs) deform irreversibly through shear banding manifested as serrated-flow behavior during compressive tests. The strain-rate-dependent plasticity under uniaxial compression at the strain rates of 2 × 10 in a Pd-based BMG is investigated. The serrated flow behavior is not observed in the stress-strain curve at the strain rate of 2 × 10 −2 · s −1 . However, the medial state occurs at the strain rates of 2 × 10 −3 · s −1 , and eventually the self-organized critical (SOC) behavior appears at the strain rate of 2 × 10 −4 · s −1 . The distribution of the elastic energy density shows a power-law distribution with the power-law exponent of −2.76, suggesting that the SOC behavior appears. In addition, the cumulative probability is well approximated by a power-law distribution function with the power-law exponent of 0.22 at the strain rate of 2 × 10 −4 · s

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Dynamics of serrated flow in a bulk metallic glass

Cited by 66 publications

References 26 publications

Temperature dependent dynamics transition of intermittent plastic flow in a metallic glass. II. Dynamics analysis

Temperature dependent dynamics transition of intermittent plastic flow in a metallic glass. II. Dynamics analysis

Serration Behavior in Pd77.5Cu6Si16.5 Alloy

The Self-Organized Critical Behavior in Pd-based Bulk Metallic Glass

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