Portevin-Le chatelier instabilities in Al-3 Mg conditioned by strain rate and strain

Balı́k, J.; Lukáč, P.

doi:10.1016/0956-7151(93)90253-o

Cited by 86 publications

(25 citation statements)

References 20 publications

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“…The critical strain, analyzed by a number of tests on substitutional alloys, has an Arrhenius type relationship with the test temperature [128]. An increase in the critical strain with increasing strain rate or with decreasing temperature is referred to as 'normal' behavior, while the opposite can also be observed and is referred to as inverse behavior [26,75,129,130]. While inverse behavior is attributed mostly to inhomogeneity, it also occurs in homogeneous solid solutions.…”

Section: Critical Strainmentioning

confidence: 99%

The Portevin–Le Chatelier effect: a review of experimental findings

Yılmaz¹

2011

Science and Technology of Advanced Materials

241

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The Portevin-Le Chatelier (PLC) effect manifests itself as an unstable plastic flow during tensile tests of some dilute alloys under certain regimes of strain rate and temperature. The plastic strain becomes localized in the form of bands which move along a specimen gauge in various ways as the PLC effect occurs. Because the localization of strain causes degradation of the inherent structural properties and surface quality of materials, understanding the effect is crucial for the effective use of alloys. The characteristic behaviors of localized strain bands and techniques commonly used to study the PLC effect are summarized in this review. A brief overview of experimental findings, the effect of material properties and test parameters on the PLC effect, and some discussion on the mechanisms of the effect are included. Tests for predicting the early failure of structural materials due to embrittlement induced by the PLC effect are also discussed.

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Section: Critical Strainmentioning

confidence: 99%

The Portevin–Le Chatelier effect: a review of experimental findings

Yılmaz¹

2011

Science and Technology of Advanced Materials

241

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“…This phenomenon and the associated negative strain rate sensitivity lead to the Portevin-LeChatelier (PLC) effect which manifests itself at the macroscopic scale [1][2][3][4]. The PLC effect consists of a discontinuous plastic flow.…”

Section: Introductionmentioning

confidence: 99%

Dislocation–solute cluster interaction in Al–Mg binary alloys

Picu

2006

Modelling Simul. Mater. Sci. Eng.

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The close-range interaction of dislocations and solute clusters in the Al-Mg binary system is studied by means of atomistic simulations. We evaluate the binding energy per unit length of dislocations to the thermodynamically stable solute atmospheres that form around their cores, at various temperatures and average solid solution concentrations. A measure of the cluster size that renders linear the relationship between the binding energy per unit length and the cluster size is identified. The variation of the interaction energy between a dislocation and a cluster residing at a finite distance from its core is evaluated and it is shown that the interaction is negligible once the separation is larger than approximately 15 Burgers vectors. The data are relevant for the dynamics of dislocation pinning during dynamic strain ageing in solid solution alloys and for static ageing.

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“…The strain rate sensitivity m is defined by [7] m ∂ logr ∂ log _ e e;T 1 m can be obtained by the power law of Equation 1, yielding a small negative strain rate sensitivity with m = -0.016. The negative strain rate sensitivity is often associated with a dynamic strain aging (DSA) in Al alloys, [8][9] which is caused by the interactions of the dislocations with the solute atoms. [9][10][11] During DSA, a lower strain rate allows fast diffusing solute atoms to diffuse to the dislocations in motion, which exerts a dragging force on moving dislocations and raises the flow stress.…”

Section: Methodsmentioning

confidence: 99%

“…The negative strain rate sensitivity is often associated with a dynamic strain aging (DSA) in Al alloys, [8][9] which is caused by the interactions of the dislocations with the solute atoms. [9][10][11] During DSA, a lower strain rate allows fast diffusing solute atoms to diffuse to the dislocations in motion, which exerts a dragging force on moving dislocations and raises the flow stress. [3] The sample deformed at e of 1 × 10 -2 s -1 has higher ductility due to the strain-hardening effect, although the strain-hardening effect is lower at relatively high strain rates.…”

Section: Methodsmentioning

confidence: 99%

Effect of Nano‐Scale Precipitates Growth on the Deformation Behavior of the Cast Coarse‐Grained Al‐Cu Alloy

Zhao

Wang

et al. 2008

Adv Eng Mater

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Al alloys are becoming increasingly significant as lightweight metal structural materials in many industries, such as aircraft construction, space technology, military field and automobile manufacturing. Therefore, it is necessary to reveal the deformation mechanisms of Al alloys to magnify their further application field.Deformation at higher strain rates is considered as a method of enhancing the ductility of nanostructured metals and alloys. [1] Higher strain rates generate crystalline defects to compete with dynamic recovery at a higher rate and therefore increase the work hardening rate, which leads to higher ductility of the nanostructured metals and alloys. [2][3][4] Despite the above reports, there are some results revealing the contradictory behavior. Cheng reported that a nanostructured Cu had higher ductility at lower strain rates. [5] The abnormal strain rates effect cannot be explained by the above deformation mechanism at higher strain rates. Recently, it is observed the similar phenomenon in the present cast coarsegrained (CG) Al-Cu alloy. So far, very little work on the higher ductility at the lower strain rates for the coarse-grained metals and alloys has been published, especially for the cast Al-Cu alloy. Therefore, the objective of this study is to investigate the reason for higher ductility at lower strain rates of 10 -4 s -1 and 10 -3 s -1 , and strain rate sensitivity at strain rates of 10 -2 s -1 and 10 -1 s -1 in the cast Al-Cu alloy modified by nano-scale Pr x O y . ExperimentalThe compositions (measured by an ARL 4460 Metals Analyzer) of the cast Al-Cu alloy were (in wt.%) 6.0 Cu, 0.15 Mn, 0.25 Ti, 0.13 V, 0.13 Zr, 0.001 B and balance Al. Details of the fabrication process for the present Al-Cu alloys are described elsewhere. [6] The heat-treated cast Al-Cu alloys were cut into tensile dog-bone shaped specimens with a gauge cross-section of 2.5 mm × 2.0 mm and a gauge length of 8.0 mm. Specimen surfaces were polished to a mirror-like finish surface. The uniaxial tensile tests at room temperature were carried out on an MTS-810 tester (U.S.A.) at the strain rate (e) ranging from 1 × 10 -4 s -1 to 1 × 10 -1 s -1 . The tensile ductility in this study was measured by calculating the gauge length change of the specimen before and after the tensile test. The mechanical property data (with a typical uncertainty of ± 1 %) in this study are the mean value of at least two specimens. Fracture morphologies and microstructures were examined with a scanning electron microscope (SEM) (Model JSM-5310, Japan) and the transmission electron microscope (TEM) (JEM-2000FX, Japan), respectively. Figure 1 shows the typical TEM microstructures of the present Al-Cu alloy after the tensile test at e of (a) 1 × 10 -4 s -1 , (b) 1 × 10 -2 s -1 , (c) 1 × 10 -3 s -1 and (d) 1 × 10 -4 s -1 , respectively. As shown in Figure 1(a), some dislocations are tangled around the nano-scale needle-like precipitates. The nanoscale needle-like precipitates were identified as the h′ phase precipitates with a composition of Al 2 Cu ...

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Portevin-Le chatelier instabilities in Al-3 Mg conditioned by strain rate and strain

Cited by 86 publications

References 20 publications

The Portevin–Le Chatelier effect: a review of experimental findings

The Portevin–Le Chatelier effect: a review of experimental findings

Dislocation–solute cluster interaction in Al–Mg binary alloys

Effect of Nano‐Scale Precipitates Growth on the Deformation Behavior of the Cast Coarse‐Grained Al‐Cu Alloy

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