Some aspects of cross-slip mechanisms in metals and alloys

Caillard, D.; Martin, J.L.

doi:10.1051/jphys:0198900500180245500

Cited by 39 publications

(8 citation statements)

References 32 publications

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“…The decrease in the activation volume with stress suggests that a stress-assisted thermally activated mechanism like cross slip is the dominant deformation process at the test conditions. The true activation volume values in the range of 70-190 b 3 are in fairly good agreement with a cross-slip process [16,33].…”

Section: Cross Slip As the Rate Controlling Mechanismsupporting

confidence: 58%

“…Cross slip has been proposed as the rate controlling mechanism in several FCC [32,33] and HCP metals such as magnesium and zinc [20,34]. Very few studies, however, treated the cross slip of screw dislocations as a viable mechanism for deformation in zirconium in high temperature quasi-static tensile testing [35,36].…”

Section: Cross Slip As the Rate Controlling Mechanismmentioning

confidence: 99%

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Dislocation cross-slip controlled creep in Zircaloy-4 at high stresses

Kombaiah

Murty

2015

Materials Science and Engineering: A

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a b s t r a c tUniaxial creep tests were performed on Zircaloy-4 sheet in the temperature range of 500-600 1C at high stresses ( 410 À 3 E), to uncover the rate-controlling mechanism. A stress exponent of 9.3-11 and a stressdependent activation energy in the range of 220-242 kJ/mol were obtained from the steady state creep data. TEM analyses revealed an extensive presence of hexagonal screw dislocation network on the basal planes indicating recovery of screw dislocations by cross-slip to be the dominant mechanism. The creep data was therefore analyzed in the light of Friedel's cross slip model for HCP metals according to which the stress-dependency of the activation energy determined from the creep data was written in the form,The constriction energy of screw dislocations of 150 kJ/mol is in agreement with the values reported in the literature for zirconium and other HCP metals. Further analysis of the yield strength and the activation volume data obtained from stress relaxation tests in the temperature range 500-600 1C favors cross-slip of screw dislocations as the rate controlling mechanism over the test conditions.

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Section: Cross Slip As the Rate Controlling Mechanismsupporting

confidence: 58%

Section: Cross Slip As the Rate Controlling Mechanismmentioning

confidence: 99%

Dislocation cross-slip controlled creep in Zircaloy-4 at high stresses

Kombaiah

Murty

2015

Materials Science and Engineering: A

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“…This process of partial dissociation may be the result of the dislocation core modification, which is known as the formation of constrictions. Caillard and Martin believed that these constrictions caused the local expansion of the dislocation core on the adjacent glide planes, corresponding to the formation of an intrinsic stacking fault I 1 that is enclosed between two partial dislocations . The partial dislocations were generally divided into Frank–Shockley partial dislocations with b = 1/6⟨202̅3⟩, depending on their mobile characteristics …”

Section: Resultsmentioning

confidence: 99%

“…Caillard and Martin believed that these constrictions caused the local expansion of the dislocation core on the adjacent glide planes, corresponding to the formation of an intrinsic stacking fault I 1 that is enclosed between two partial dislocations. 34 The partial dislocations were generally divided into Frank−Shockley partial dislocations with b = 1/6⟨202̅ 3⟩, depending on their mobile characteristics. 35 Figure 7 illustrates the thermally activated nucleation of Shockley partials under the conditions of T = 2200 K and σ yx = 3 GPa.…”

Section: Simulation Methodsmentioning

confidence: 99%

Molecular Dynamics Simulations of the Thermally and Stress-Activated Glide of a ⟨0001⟩{11̅00} Screw Dislocation in AlN

Zhao

Wang²,

et al. 2021

Crystal Growth & Design

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The low-temperature plasticity of aluminum nitride (AlN) is determined by the interaction between edge and screw dislocations. However, the motion of screw dislocations and their glide mechanisms have not been evaluated. In this study, the motion of a ⟨0001⟩{11̅ 00} screw dislocation in a single crystal of AlN is explored by molecular dynamics simulations using LAMMPS software with the Stillinger−Weber (SW) potential. Four modes of thermally activated motion are observed under different conditions of temperature and stress: double kinks, Shockley partials, self-pinning, and debris and dislocation loops. The mobilities of a ⟨0001⟩{11̅ 00} screw dislocation and a 1/3⟨112̅ 0⟩{11̅ 00} edge dislocation are compared under various conditions. Our results show that the mobilities of the ⟨0001⟩{11̅ 00} screw and 1/3⟨112̅ 0⟩{11̅ 00} edge dislocations are quite low at T < 600 K. The ⟨0001⟩{11̅ 00} screw dislocation moves faster at 900 < T < 1500 K and seems less dependent on the temperature than does the 1/3⟨112̅ 0⟩{11̅ 00} edge dislocation at 1200 < T < 2200 K. However, the opposite phenomenon is observed at higher temperatures. The mobility of the ⟨0001⟩{11̅ 00} screw dislocation is slightly lower than that of the 1/3⟨112̅ 0⟩{11̅ 00} edge dislocation at T > 1800 K, although the mobility difference can reach several orders of magnitude at 900 < T < 1200 K due to different Peierls barriers.

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“…For the Pt dewetted particle, the two segments lie in a (101̅) plane. As the particle has been formed after dewetting at high temperature (1000 °C), it is possible that the dislocations form at high temperature during the cooling process (thermal stress) as slip in {110} planes is known to be thermally activated . Several groups have observed a nonoctahedral slip in Pt in the past and during deformation (see for examples, refs. , ).…”

Section: Discussionmentioning

confidence: 99%

Anomalous Glide Plane in Platinum Nano- and Microcrystals

et al. 2023

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At the nanoscale, the properties of materials depend critically on the presence of crystal defects. However, imaging and characterizing the structure of defects in three dimensions inside a crystal remain a challenge. Here, by using Bragg coherent diffraction imaging, we observe an unexpected anomalous {110} glide plane in two Pt submicrometer crystals grown by very different processes and having very different morphologies. The structure of the defects (type, associated glide plane, and lattice displacement) is imaged in these faceted Pt crystals. Using this noninvasive technique, both plasticity and unusual defect behavior can be probed at the nanoscale.

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Some aspects of cross-slip mechanisms in metals and alloys

Abstract: Résumé. 2014

Cited by 39 publications

References 32 publications

Dislocation cross-slip controlled creep in Zircaloy-4 at high stresses

Dislocation cross-slip controlled creep in Zircaloy-4 at high stresses

Molecular Dynamics Simulations of the Thermally and Stress-Activated Glide of a ⟨0001⟩{11̅00} Screw Dislocation in AlN

Anomalous Glide Plane in Platinum Nano- and Microcrystals

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