Theory of the effect of dynamic strain aging on mechanical properties

Beukel, A. van den

doi:10.1002/pssa.2210300120

Cited by 569 publications

(67 citation statements)

References 4 publications

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“…This mechanism is called the Dynamic Strain Ageing (DSA) [Cottrell, 1953] and it is now reasonably understood, at least qualitatively. It is quite generally agreed [van den Beukel, 1975;Estrin & Kubin, 1989] that the dynamic interaction of the various types of defects is responsible for the occurrence of a negative strain rate sensitivity. This, in turn, leads to an instability of the homogeneous deformation within a certain window of control parameters such as temperature, imposed strain rate, solute concentration, etc.…”

Section: Introductionmentioning

confidence: 99%

Chaos in the Portevin–Le Châtelier Effect

Noronha

Ananthakrishna

Quaouire

et al. 1997

Int. J. Bifurcation Chaos

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We report the verification of the prediction of chaos in the Portevin-Le Châtelier effect or the jerky flow by analyzing the stress signals obtained from samples of polycrystalline Al-Mg alloys subjected to a constant strain rate test. Particular care is taken to obtain reasonably long and accurate stress signals. The analysis of these signals is carried out by using several complementary methods such as calculation of correlation dimension, singular value decomposition and the spectrum of Lyapunov exponents. The analysis shows the existence of a finite correlation dimension and a positive Lyapunov exponent. Using the existence of a positive Lyapunov exponent and finite correlation dimension as a discriminator, we also carry out a surrogate analysis of the time series to ascertain that the signals are not from a power law stochastic process. The analysis provides an unambiguous support for the existence of chaos in Portevin-Le Châtelier effect thus verifying the prediction of the model. Further, from the analysis we find that the minimum number of variables required for a dynamical description of the jerky flow appears to be four or five consistent with the model.

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Section: Introductionmentioning

confidence: 99%

Chaos in the Portevin–Le Châtelier Effect

Noronha

Ananthakrishna

Quaouire

et al. 1997

Int. J. Bifurcation Chaos

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“…Serrated flow, one of the characteristics of DSA, was not observed in AR and AQ samples. The serrated flow occurs when the solute atoms move to the dislocations and prevent their motion [20][21][22] . It is now well accepted that serrated yielding exhibited by a material occurs due to interaction between diffusing solute atoms and dislocations 23 .…”

Section: Resultsmentioning

confidence: 99%

The Effect of Heat Treatment on Dynamic Strain Aging Behaviour of AISI H10 Hot Work Tool Steel

Taştemür

Gündüz

2017

Mat. Res.

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Dynamic strain aging (DSA) behaviour of hot work tool steel (H10) was investigated under asreceived (AR) and as-quenched (AQ) conditions. Hot tensile test was carried out in the temperatures of 25°C-700°C at a strain rate of 1x10 -3 s -1 . The tensile properties indicated that AQ samples showed an increase in yield strength (YS) and ultimate tensile strength (UTS) but a decrease in elongation at 200°C or 300°C consistent with DSA. However, AR samples revealed a decrease in YS and UTS for the same testing temperatures. This indicated the presence of less amount of free C or N in solution of AR samples. Further increase in the testing temperature has increased the elongation. It is believed that DSA occurs in H10 tool steel at different temperatures because of interaction between dislocations and interstitial solute atoms (C or N) or substitutional atoms (Cr or Mo).

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“…The moment of a break-off of a dislocation from the blocking atoms involves a sudden drop in the force exciting the deformation. [18][19][20] According to the dislocation-dynamic model of the PLC effect, every local drop in the loading force recorded on the s -e curves is connected with unlocking the dislocation sources in a certain localized area of the sample. If there is a high concentration of internal stresses, the adjacent sources of dislocation will, successively, become unlocked due to these stresses.…”

Section: Resultsmentioning

confidence: 99%

Influence of the strain rate on the PLC effect and acoustic emission in single crystals of the CuZn30 alloy compressed at an elevated temperature

Ozgowicz¹,

Grzegorczyk²,

Pawełek³

2015

Mater. Tehnol.

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The purpose of these investigations was to determine the effect of the strain rate on the phenomenon of a heterogeneous plastic deformation of the Portevin-Le Chatelier type while testing free compression of CuZn30 single crystals with a crystallographic orientation of [139] at 300°C. Moreover, the relations between the work-hardening curve s -e displaying the PLC effect and the characteristics of the signals of the acoustic emission generated in the uniaxial-compression test were determined. It was found that the process of plastic deformation of the tested single crystals in the analyzed range of the frequencies up to 35 kHz generates differentiated sources of acoustic-energy emission, mainly the impulsive emission generated by signal events, correlated with the oscillations of the stresses on the work-hardening curves s -e. The strain rate mainly causes the changes in the intensity of the oscillation typical for the PLC effect. Keywords: plastic strain, Portevin-Le Chatelier effect (PLC), single crystals, copper alloys, compression test, acoustic emission (AE) Namen raziskav je bil ugotoviti vpliv hitrosti deformiranja pri preizkusu stiskanja monokristalov CuZn30 s kristalografsko orientacijo [139] pri 300°C na pojav heterogene plasti~ne deformacije vrste Portevin-Le Chatelier. Poleg tega so bile ugotovljene {e odvisnosti med krivuljo deformacijskega utrjevanja s -e, ki ka`e pojav PLC, in zna~ilnostmi signalov akusti~ne emisije pri enoosnem tla~nem preizkusu. Ugotovljeno je, da proces plasti~ne deformacije preizku{anih kristalov v analiziranem podro~ju frekvenc do 35 kHz proizvaja diferencirane vire emisije akusti~ne energije, predvsem impulzivne emisije signalov, ki se skladajo z oscilacijo napetosti na krivulji deformacijskega utrjevanja s -e. Hitrost deformacije se ka`e predvsem v spremembi intenzitete oscilacij, zna~ilnih za PLC-pojav. Klju~ne besede: plasti~na deformacija, Portevin-Le Chatelierov pojav (PLC), monokristali, zlitine bakra, tla~ni preizkus, akusti~na emisija (AE)

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Theory of the effect of dynamic strain aging on mechanical properties

Cited by 569 publications

References 4 publications

Chaos in the Portevin–Le Châtelier Effect

Chaos in the Portevin–Le Châtelier Effect

The Effect of Heat Treatment on Dynamic Strain Aging Behaviour of AISI H10 Hot Work Tool Steel

Influence of the strain rate on the PLC effect and acoustic emission in single crystals of the CuZn30 alloy compressed at an elevated temperature

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