Journal ArticleDOI
Direct evidence of dislocation transmission through ∊= 9 grain boundaries in germanium and silicon by in situ high-voltage electron microscopy observations
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The microscopy electronique is a haute tension, utilise dans l'etude in situ de la deformation de bicristaux de silicium and de germanium, a revele que des dislocations traversaient des joints de grains e=9, meme lorsque leurs vecteurs de Burgers n'etaient pas vecteur de reseau du deuxieme grain.Abstract:
Le microscope electronique a haute tension, utilise dans l'etude in situ de la deformation de bicristaux de silicium et de germanium, a revele que des dislocations traversaient des joints de grains e=9, meme lorsque leurs vecteurs de Burgers n'etaient pas vecteurs de reseau du deuxieme grain. Ces dislocations sont parfaites (b=1/2 ) ou, le plus souvent, partielles de Shockley, entrai←nant des defauts d'empilement lies au joint. Les dislocations peuvent se dissocier dans le joint en dislocations glissiles DSC; les dislocations residuelles peuvent etre deplacees. Les caracteristiques observees de ce phenomene peuvent s'expliquer par un modele base sur des calculs des energies des configurations possibles des dislocations formees lors des etapes successives du processus de transmissionread more
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Breakdown of avalanche critical behaviour in polycrystalline plasticity
TL;DR: It is shown that polycrystalline plasticity is also characterized by intermittency and dislocation avalanches, and the restraint of large avalanches builds up internal stresses that push temporally the dynamical system into a supercritical state, off the scale-invariant critical regime, and trigger secondary avalanches in neighbouring grains.
Journal ArticleDOI
Dislocation loops at crack tips: nucleation and growth— an experimental study in silicon
TL;DR: In this paper, the nucleation of dislocation loops at crack tips and the development of the plastic zone were studied in single-crystal silicon samples precracked at room temperature and loaded at T ⩾ 900 K under well-controlled conditions (mode I loading, constant loading rate).
Journal ArticleDOI
Dislocation avalanches: Role of temperature, grain size and strain hardening
TL;DR: In this article, the authors investigate the possible incidence of temperature and microstructure on the emerging pattern of the scale-free pattern of an avalanche, and reveal the role of grain boundaries as barriers to dislocation motion hindering the emergence of the scalesafe pattern.
Journal ArticleDOI
Orientation Gradients at Boundaries in Micron‐Sized Bicrystals
Nousha Kheradmand,Horst Vehoff +1 more
TL;DR: In this paper, electron back scattering diffraction (EBSD) was used to study dislocation pile-ups at boundaries in micron-sized Ni bicrystals, after compression tests, orientation gradients were measured by EBSD.
References
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Book
Dislocations in solids
TL;DR: In this article, Bertotti, Ferro, and Mazetti proposed a theory of dislocation drag in covalent crystals and formed a model of the formation and evolution of dislocations during irradiation.
Journal ArticleDOI
Dislocation pile-up and grain boundary interactions in 304 stainless steel
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Grain boundary accommodation of slip in Ni3Al containing boron
TL;DR: In this article, it was shown that the addition of 750 ppm by weight (0.35 at%) of boron to stoichiometric Ni3Al reduces the effectiveness with which grain boundaries strengthen the alloy.
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The effects on grain-boundary processes of the steps in the boundary plane associated with the cores of grain-boundary dislocations
Alexander H. King,D. A. Smith +1 more
TL;DR: The contribution of the associated steps to the properties of grain-boundary dislocations is investigated in this paper, where two methods of step-height determination are given and it is shown that the step height, like the Burgers vector, must be conserved during the reactions of grain boundaries, this is not always automatic and additional coherent steps must take part in some reactions.
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Velocities of screw and 60° dislocations in n- and p-type silicon
A. George,G. Champier +1 more
TL;DR: The effect of doping on the dislocation velocity is discussed mainly in terms of Haasen's calculation of the influence of the electrical charge carried by the dislocations on the formation of a double kink as mentioned in this paper.