Dislocation multiplication, vacancy accumulation, and the onset of jerky flow during forward and reverse 1 strain in Cu-3.2 at. % Sn

Ham, Robert K.; Jaffrey, D.

doi:10.1080/14786436708227697

Cited by 121 publications

(8 citation statements)

References 18 publications

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“…It is also worth noting that unlike in other materials, we did not observe any systematic critical strain for the appearance of the PLC effect for a given temperature and strain rate range nor did the amplitudes and frequency of load drops vary systematically. Thus, any attempts to characterize the activation energy using a model in which the critical strain is a component [4] would not be applicable to the data presented in this paper nor would approaches using the so-called stress decrement which have been proposed for Waspaloy [8] and for alloy 720 Li, [10] both Ni-based superalloys. In this study, the activation energy was determined by using the tensile results to create a map in terms of temperature and strain rates showing the regions in which PLC did and did not occur.…”

Section: A Tensile Resultsmentioning

confidence: 85%

“…Thus, following a procedure suggested elsewhere, [22] the slope of a graph of the natural logarithm of the strain rate vs 1/T separating the two re´gimes of behavior yields the apparent activation energy provided that Eq. [4] correctly represents the deformation process.…”

Section: Determination Of Activation Energymentioning

confidence: 92%

“…Most results show that the PLC effect arises from a dynamic interaction between dislocations and solute atoms. The PLC effect has been observed in solid solution alloys [2][3][4][5][6][7] and also in precipitate systems such as Ni-based superalloys e.g., References 8 through 12 and in Ni-Fe base superalloys, e.g., Reference 13. In broad outline, the solute atoms segregate to regions in the lattice which are dilated by the presence of dislocations to reduce the overall strain energy of the system.…”

Section: Introductionmentioning

confidence: 97%

See 2 more Smart Citations

The Portevin-Le Chatelier Effect in the Ni-Based Superalloy IN100

Fernandez-Zelaia

Adair

Barker

et al. 2015

Metall Mater Trans A

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The Portevin-Le Chatelier (PLC) effect has been studied in the Ni-based superalloy IN100 which is currently used as a disk material in jet engines. A series of tensile tests was carried out at 588 K, 755 K, and 922 K (315°C, 482°C, and 649°C) at plastic strain rates ranging from a low of 6.21 9 10 À6 s À1 to a high of 4.92 9 10 À2 s À1 . The activation energy was determined using the slope of a line on a strain rate/temperature graph which divided the area of the graph into two regions: (1) ''PLC behavior observed,'' and (2) ''No PLC behavior observed.'' A new statistical approach was developed to objectively differentiate between a true PLC effect and experimental uncertainty (i.e., ''noise''). The value of the activation energy was found to be 1.14 eV/atom, which strongly suggests that the rate controlling process was bulk diffusion of C in the lattice. A qualitative model, based on the Orowan equation and slip band dislocation mechanics, was proposed, which unifies the seemingly disparate ideas of the process being controlled by a single atom/dislocation interaction while at the same time exhibiting significant strains during PLC load drops.

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Section: A Tensile Resultsmentioning

confidence: 85%

Section: Determination Of Activation Energymentioning

confidence: 92%

Section: Introductionmentioning

confidence: 97%

See 1 more Smart Citation

The Portevin-Le Chatelier Effect in the Ni-Based Superalloy IN100

Fernandez-Zelaia

Adair

Barker

et al. 2015

Metall Mater Trans A

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“…When the deformation continues, the dislocations have to break away from these atmospheres and multiply. This leads to serrated yielding [15][16][17] ). The higher densities of dislocation and grain boundary introduced by strain hardening can hold the mobile dislocations long enough to let Mg atoms form atmospheres around them.…”

Section: Discussionmentioning

confidence: 99%

Pre-Treated Effect of Friction Stir Processing of Al Alloy 5052 on Vibration Fracture Behavior under Resonant Vibration

2005

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In this study, 5052 Al-Mg alloy was pre-treated and friction stir processing (FSP) was then performed on the specimens to explore the deformation resistance. The experimental results indicate that the FSP specimens not only had better tensile properties but also better vibration fracture resistance. It is significant that the tensile elongation and deformation resistance tended to increase as the grain was refined by friction stir processing. Results show that the use of FSP yielded uniform hardness distribution and slightly larger n values which improved the vibration fracture resistance of the specimens. However, even without FSP, more uniform elongation and larger n values could still improve the vibration fracture resistance of the specimens. Consequently, the uniform elongation and larger n values play an important role in increasing vibration fracture resistance. As for crack propagation, the FSP specimens revealed only a few slip bands in the vicinity of the main crack, and the 5052H34 specimen displayed a few slip bands in the vicinity of the main crack. However, more slip bands were observed in the vicinity of the main crack on the 5052-O specimens, and there were deformation traces and advancing cracks rising at the front of the main crack. Consequently, vibration fracture resistance can also be better improved if the crack initiation and propagation through the stir zone of FSP specimens are controlled. This is correlated with the formation of fine grains through dynamic recrystallization in the vicinity of stir zone.

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“…5,7,8) The dynamic strain aging is caused by an interaction between solute atoms and moving dislocations. The possible types of interacted solute atoms in FCC metals are (1) interstitial atoms, 9) (2) substitutional atoms, 10) and (3) interstitial atom-substitutional atom couples. 5,11) The dynamic strain aging in FeMnC steels has been reported to be attributed to the interaction between moving dislocations and MnC couples.…”

Section: Introductionmentioning

confidence: 99%

Influence of Dislocation Separation on Dynamic Strain Aging in a Fe–Mn–C Austenitic Steel

2012

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The influences of deformation temperature and strain rate on the serrated flow behavior of a Fe17Mn0.3C alloy with a low stacking fault energy were investigated by the tensile tests in a temperature range of 273 to 523 K. Three regions were found when the deformation temperature was plotted against the critical strains for the onset of serrations. The critical strain decreased in the region of 273 to 323 K, increased in that of 323 to 423 K, and decreased again in that of 423 to 523 K with increasing temperature. The first two regions are well known. However, the third region corresponding to that of high temperature has not been reported, and this region could be interpreted by separately considering the interactions of solute atoms with leading and trailing partials. Since the velocity of the leading partials is assumed to be significantly higher than that of the trailing partials, the critical strains in the first and third regions were concluded to result from trapping the trailing partials and the leading partials, respectively.

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Dislocation multiplication, vacancy accumulation, and the onset of jerky flow during forward and reverse 1 strain in Cu-3.2 at. % Sn

Cited by 121 publications

References 18 publications

The Portevin-Le Chatelier Effect in the Ni-Based Superalloy IN100

The Portevin-Le Chatelier Effect in the Ni-Based Superalloy IN100

Pre-Treated Effect of Friction Stir Processing of Al Alloy 5052 on Vibration Fracture Behavior under Resonant Vibration

Influence of Dislocation Separation on Dynamic Strain Aging in a Fe–Mn–C Austenitic Steel

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Dislocation multiplication, vacancy accumulation, and the onset of jerky flow during forward and reverse 1 strain in Cu-3.2 at. % Sn

Cited by 121 publications

References 18 publications

The Portevin-Le Chatelier Effect in the Ni-Based Superalloy IN100

The Portevin-Le Chatelier Effect in the Ni-Based Superalloy IN100

Pre-Treated Effect of Friction Stir Processing of Al Alloy 5052 on Vibration Fracture Behavior under Resonant Vibration

Influence of Dislocation Separation on Dynamic Strain Aging in a Fe&ndash;Mn&ndash;C Austenitic Steel

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Influence of Dislocation Separation on Dynamic Strain Aging in a Fe–Mn–C Austenitic Steel