{112} &lt;23&gt; slip in titanium

Minonishi, Y.; Morozümi, Shotaro; Yoshinaga, Hideo

doi:10.1016/0036-9748(82)90166-1

Cited by 70 publications

(29 citation statements)

References 7 publications

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“…Frequent cross-slip of hc + ai dislocations can occur in early stage, room temperature deformation (10-15). However, the propensity and nature of hc + ai cross-slip differ among different materials and can also depend on the applied stress and temperature in the same material (12,(16)(17)(18)(19)(20)(21)(22) (Fig. 2 and refs.…”

mentioning

confidence: 99%

Mechanism and energetics of 〈c + a〉 dislocation cross-slip in hcp metals

Curtin

2016

Proc. Natl. Acad. Sci. U.S.A.

110

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Hexagonal close-packed (hcp) metals such as Mg, Ti, and Zr are lightweight and/or durable metals with critical structural applications in the automotive (Mg), aerospace (Ti), and nuclear (Zr) industries. The hcp structure, however, brings significant complications in the mechanisms of plastic deformation, strengthening, and ductility, and these complications pose significant challenges in advancing the science and engineering of these metals. In hcp metals, generalized plasticity requires the activation of slip on pyramidal planes, but the structure, motion, and cross-slip of the associated 〈c + a〉 dislocations are not well established even though they determine ductility and influence strengthening. Here, atomistic simulations in Mg reveal the unusual mechanism of 〈c + a〉 dislocation cross-slip between pyramidal I and II planes, which occurs by cross-slip of the individual partial dislocations. The energy barrier is controlled by a fundamental step/ jog energy and the near-core energy difference between pyramidal 〈c + a〉 dislocations. The near-core energy difference can be changed by nonglide stresses, leading to tension-compression asymmetry and even a switch in absolute stability from one glide plane to the other, both features observed experimentally in Mg, Ti, and their alloys. The unique cross-slip mechanism is governed by common features of the generalized stacking fault energy surfaces of hcp pyramidal planes and is thus expected to be generic to all hcp metals. An analytical model is developed to predict the cross-slip barrier as a function of the near-core energy difference and applied stresses and quantifies the controlling features of cross-slip and pyramidal I/II stability across the family of hcp metals.P lastic deformation of crystalline materials occurs mainly by slip along low-index atomic planes. Slip regions are bounded by line defects called dislocations (1), which are characterized by the crystallographic slip increment known as the Burgers vector b and the local line direction ξ. The transition from slipped to unslipped regions is resolved at the atomic scale by local atomic rearrangements creating a dislocation "core" structure. Slip occurs by motion of this core, and the surrounding elastic fields, driven by an applied stress. Plasticity is thus controlled by the details of the core region, which differ significantly among face-centered cubic (fcc), bodycentered cubic (bcc), and hexagonal close-packed (hcp) metals (2). The motion of the dislocation core is usually confined to glide within the slip plane defined by the normal vector n = b × ξ. Screw dislocations have b × ξ = 0, however, and so do not have a unique slip plane and can therefore "cross-slip" among glide planes that share a common Burgers vector. Cross-slip is a crucial process in plasticity, acting to spread slip spatially on multiple nonparallel planes and to enable dislocation multiplication and annihilation processes; all of these processes affect ductility and ultimate strength of the material. Whereas the atomistic mecha...

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confidence: 99%

Mechanism and energetics of 〈c + a〉 dislocation cross-slip in hcp metals

Curtin

2016

Proc. Natl. Acad. Sci. U.S.A.

110

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“…This finding contradicts previous results in which twinning assisted the activation of ha þ ci slip for strain accommodation. [6][7][8]10) In samples compressed at 623 K, narrow lamellae type twin bands with a width of 200 nm are distributed throughout the whole area and the character of these twins is revealed as f10 1 11g twin, as shown in Fig. 2(b).…”

Section: Resultsmentioning

confidence: 99%

“…5) Thus it is generally accepted that deformation twinning helps the activation of hai slip to accommodate plastic strain imposed by deformation processes. [6][7][8] It was observed that deformation twinning occured in f10 2 22g, f11 2 21g, and f11 2 22g planes at ambient temperatures and f10 1 11g plane above 673 K. 9) Furthermore, deformation twins were found to enhance slip along the h11 2 23i direction (i.e., ha þ ci slip) on f 1 1011g or f 1 1 1 122g planes at elevated temperature. 8,10) In order to achieve ultra fine grains, equal channel angular pressing (ECAP) has been widely used to produce severe strain.…”

Section: Introductionmentioning

confidence: 99%

“…[6][7][8] It was observed that deformation twinning occured in f10 2 22g, f11 2 21g, and f11 2 22g planes at ambient temperatures and f10 1 11g plane above 673 K. 9) Furthermore, deformation twins were found to enhance slip along the h11 2 23i direction (i.e., ha þ ci slip) on f 1 1011g or f 1 1 1 122g planes at elevated temperature. 8,10) In order to achieve ultra fine grains, equal channel angular pressing (ECAP) has been widely used to produce severe strain. [11][12][13][14] It was found that f10 1 11g twinning was a main deformation mode of commercial pure (CP) titanium ECAPed at 623 K. 9,[15][16][17][18] This finding was inconsistency in a well-known fact that titanium is deformed mainly by dislocation slip with some assistance from deformation twins.…”

Section: Introductionmentioning

confidence: 99%

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Deformation Mechanism of Severely Deformed CP-Titanium by Uniaxial Compression Test

Kim

Shin

et al. 2008

Mater. Trans.

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“…Par contre les dislocations c + a coins glissent uniquement dans le plan {1122}. De multiples observations en MET dans différents alliages de titane et de zirconium ont confirmé les travaux de Bacon [12,41,[63][64][65]. La contrainte de cisaillement critique c , comme la sensibilité à la vitesse de déformation plastique, est bien supérieure à celle des autres systèmes de glissement.…”

Section: Facilité Relative Des Modes De Glissement Dans Les Métaux Hcunclassified

Influence de l'hydrogène sur les mécanismes de déformation et d'endommagement des alliages de titane et de zirconium

Feaugas

Conforto

2009

PlastOx 2007 - Mécanismes Et Mécanique Des Interactions Plasticité - Environnement

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Résumé. L'hydrogène, élément rarement dissociable des alliages de titane et de zirconium, confèrent à ceux-ci des propriétés physico-chimiques particulières dont les conséquences sur les processus de déformation et d'endommagement sont incontestables. A travers cet écrit nous faisons une synthèse des résultats acquis dans ce domaine en nous attachant à préciser les relations connues entre les différents états microstructuraux des alliages et les propriétés mécaniques. Le point le plus marquant, dans ce contexte, est le rôle du couple oxygène-hydrogène sur les mécanismes de déformation et d'endommagement.

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{112} <23> slip in titanium

Cited by 70 publications

References 7 publications

Mechanism and energetics of 〈c + a〉 dislocation cross-slip in hcp metals

Mechanism and energetics of 〈c + a〉 dislocation cross-slip in hcp metals

Deformation Mechanism of Severely Deformed CP-Titanium by Uniaxial Compression Test

Influence de l'hydrogène sur les mécanismes de déformation et d'endommagement des alliages de titane et de zirconium

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