Thermally activated slip deformation of high purity iron single crystals between 4.2 K and 300 K

Kuramoto, Eiichi; Aono, Yasuhisa; Kitajima, K.

doi:10.1016/0036-9748(79)90199-6

Cited by 102 publications

(43 citation statements)

References 14 publications

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“…2(b)) is different from their bulk single crystal counterparts. In bulk single crystals, the yield stress generally saturates above a critical temperature [48][49][50][51] . In BCC Fe nanowires, saturation in yield stress has not been observed.…”

Section: A Temperature Dependence Of Yield Stressmentioning

confidence: 99%

Atomistic simulations on ductile-brittle transition in ⟨111⟩ BCC Fe nanowires

Sainath

Choudhary

2017

Journal of Applied Physics

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Molecular dynamics simulations have been performed to understand the influence of temperature on the tensile deformation and fracture behavior of <111> BCC Fe nanowires. The simulations have been carried out at different temperatures in the range 10-1000 K employing a constant strain rate of 1× 10 8 s −1 . The results indicate that at low temperatures (10-375 K), the nanowires yield through the nucleation of a sharp crack and fails in brittle manner. On the other hand, nucleation of multiple 1/2<111> dislocations at yielding followed by significant plastic deformation leading to ductile failure has been observed at high temperatures in the range 450-1000 K. At the intermediate temperature of 400 K, the nanowire yields through nucleation of crack associated with many mobile 1/2<111> and immobile <100> dislocations at the crack tip and fails in ductile manner. The ductile-brittle transition observed in <111> BCC Fe nanowires is appropriately reflected in the stress-strain behavior and plastic strain at failure. The ductile-brittle transition increases with increasing nanowire size. The change in fracture behavior has been discussed in terms of the relative variations in yield and fracture stresses and change in slip behavior with respect to temperature. Further, the dislocation multiplication mechanism assisted by the kink nucleation from the nanowire surface observed at high temperatures has been presented.

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Section: A Temperature Dependence Of Yield Stressmentioning

confidence: 99%

Atomistic simulations on ductile-brittle transition in ⟨111⟩ BCC Fe nanowires

Sainath

Choudhary

2017

Journal of Applied Physics

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“…Figure 5 shows the experimental results of the temperature dependence of yield stress of iron single crystals and polycrystals. 27,28) It is clear that the temperature dependence of the yield stress, in particular at a lower-temperature region, can be reproduced excellently by the curves T / f1 À ð¸=¸PÞg 5=4 for p = 2. Conducting further analysis, it is possible to derive the following equations for the activation volume v Ã and the kink width w Ã .…”

Section: Thermally Activated Deformation By the Peierls Mechanism In mentioning

confidence: 88%

“…Conducting further analysis, it is possible to derive the following equations for the activation volume v Ã and the kink width w Ã . Fe polycrystal (27) Fe single crystals (28) Temperature / K…”

Section: Thermally Activated Deformation By the Peierls Mechanism In mentioning

confidence: 99%

Selected Topics on Material Strength and Thermally Activated Deformation Processes

Kato

2015

Mater. Trans.

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Thermally activated deformation processes are discussed with reference to the studies done by the present author and his coworkers. First, dislocation motion in one-and two-dimensional periodic stress fields is analyzed to understand the deformation mechanisms of bcc metals and spinodally decomposed alloys. The role of the thermally activated kink-pair formation on the temperature and strain-rate dependence of strength is also discussed. Secondly, diffusion-controlled processes pertinent to high-temperature deformation are discussed by applying a unified and fundamental rate equation derived previously. Thirdly, mechanisms for the temperature and strain-rate dependence of polycrystals and ultrafinegrained and nanocrystalline materials are introduced. A proposed model taking into account the thermally activated dislocation depinning at grain boundaries is discussed.

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“…Le comportement sur le système primaire est ainsi représenté sur la figure 2a) en fonction de la température. Un point de comparaison intéressant par rapport à des résultats expérimentaux [12][13][14][15] et de simulations en DDD [1] est l'évolution de la cission critique lors de l'entrée en plasticité en fonction de la température. Cette comparaison est représentée sur la figure 2b et l'on constate une bonne reproduction de cette évolution par la loi de plasticité cristalline.…”

Section: Premiers Résultats De Simulationunclassified

“…Cela n'est en soit pas trop surprenant dans la mesure où la loi d'écoulement (4) s'inspire fortement de la loi de mobilité introduite dans les simulations de DDD [1]. Concernant l'écrouissage, on peut constater sur la figure 2a) que celui-ci augmente avec la température (surtout en relatif par rapport à la cission critique), ce qui est en accord avec des résultats expérimentaux de [14].…”

Section: Premiers Résultats De Simulationunclassified

Loi de comportement en plasticité cristalline pour acier à basse température

Monnet

Vincent

2011

Mécanique & Industries

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Thermally activated slip deformation of high purity iron single crystals between 4.2 K and 300 K

Cited by 102 publications

References 14 publications

Atomistic simulations on ductile-brittle transition in ⟨111⟩ BCC Fe nanowires

Atomistic simulations on ductile-brittle transition in ⟨111⟩ BCC Fe nanowires

Selected Topics on Material Strength and Thermally Activated Deformation Processes

Loi de comportement en plasticité cristalline pour acier à basse température

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