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Mechanisms of deformation and of recrystallization of imperfect uranium monocrystals; Les mecanismes de deformation et de recristallisation des monocristaux imparfaits d'uranium

Abstract

The various means by which plastic deformations by slip, twinning or kinking are produced by tension of imperfect {alpha} uranium single crystals prepared by a {beta} {yields} {alpha} phase change, have been studied by X-rays and micrographic examination. Depending on the crystallographic orientation with respect to the direction of the applied tension, and depending on the magnitude of the change in length, the crystals are deformed either preferentially according to a single mechanism, for example twinning, or simultaneously according to two or three mechanisms. The results of a subsequent annealing of the deformed single in the {alpha} phase are studied with respect to the deformation mechanisms. In the case of a deformation due primarily to (010) [100], (011) [100] or (110) [001] sliding, there occurs recrystallization by crystal growth selectivity. If the deformation occurs via deformation bands, there is recrystallization by 'oriented nucleation'. The crystals deformed preponderantly by twinning give on recrystallization perfect crystals having optimum dimensions and having orientational characteristics closely related to those of the original crystal. Finally are discussed some criteria relating to the geometry and the dynamics with a view to explaining the occurrence of such and such a deformation mechanism of a single crystal with  More>>
Authors:
Calais, D [1] 
  1. Commissariat a l'Energie Atomique, Saclay (France). Centre d'Etudes Nucleaires
Publication Date:
Apr 15, 1960
Product Type:
Thesis/Dissertation
Report Number:
CEA-R-1734
Resource Relation:
Other Information: TH: These sciences; 46 refs
Subject:
36 MATERIALS SCIENCE; ANISOTROPY; ANNEALING; CRYSTAL GROWTH; CRYSTAL-PHASE TRANSFORMATIONS; DEFORMATION; DILATOMETRY; GRAIN SIZE; LAUE METHOD; NUCLEATION; ORTHORHOMBIC LATTICES; PHOTOMICROGRAPHY; PLASTICITY; POLYCRYSTALS; RECRYSTALLIZATION; SLIP; STRAIN HARDENING; TEMPERATURE GRADIENTS; TWINNING; URANIUM-ALPHA; X-RAY DIFFRACTION
OSTI ID:
20967963
Research Organizations:
CEA Saclay, 91 - Gif-sur-Yvette (France); Faculte des Sciences de l'Universite de Paris, 75 (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR07R1734116748
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
78 pages
Announcement Date:
Dec 29, 2007

Citation Formats

Calais, D. Mechanisms of deformation and of recrystallization of imperfect uranium monocrystals; Les mecanismes de deformation et de recristallisation des monocristaux imparfaits d'uranium. France: N. p., 1960. Web.
Calais, D. Mechanisms of deformation and of recrystallization of imperfect uranium monocrystals; Les mecanismes de deformation et de recristallisation des monocristaux imparfaits d'uranium. France.
Calais, D. 1960. "Mechanisms of deformation and of recrystallization of imperfect uranium monocrystals; Les mecanismes de deformation et de recristallisation des monocristaux imparfaits d'uranium." France.
@misc{etde_20967963,
title = {Mechanisms of deformation and of recrystallization of imperfect uranium monocrystals; Les mecanismes de deformation et de recristallisation des monocristaux imparfaits d'uranium}
author = {Calais, D}
abstractNote = {The various means by which plastic deformations by slip, twinning or kinking are produced by tension of imperfect {alpha} uranium single crystals prepared by a {beta} {yields} {alpha} phase change, have been studied by X-rays and micrographic examination. Depending on the crystallographic orientation with respect to the direction of the applied tension, and depending on the magnitude of the change in length, the crystals are deformed either preferentially according to a single mechanism, for example twinning, or simultaneously according to two or three mechanisms. The results of a subsequent annealing of the deformed single in the {alpha} phase are studied with respect to the deformation mechanisms. In the case of a deformation due primarily to (010) [100], (011) [100] or (110) [001] sliding, there occurs recrystallization by crystal growth selectivity. If the deformation occurs via deformation bands, there is recrystallization by 'oriented nucleation'. The crystals deformed preponderantly by twinning give on recrystallization perfect crystals having optimum dimensions and having orientational characteristics closely related to those of the original crystal. Finally are discussed some criteria relating to the geometry and the dynamics with a view to explaining the occurrence of such and such a deformation mechanism of a single crystal with a given orientation. This study, in conclusion, must help to define the best conditions (crystalline orientation and process of deformation) which will promote the growth of large, perfect, single crystals. (author) [French] Les divers modes de deformation plastique, glissement, maclage et pliage, que provoque la traction de monocristaux d'uranium {alpha} imparfaits prepares par changement de phase {beta} {yields} {alpha} ont ete etudies par rayons X et par examen micrographique. Suivant l'orientation cristallographique par rapport a la direction de l'axe de traction et suivant l'importance de l'allongement, les monocristaux se deforment, soit preferentiellement suivant un seul mecanisme, tel que le maclage, soit simultanement suivant deux ou trois mecanismes. Les consequences d'un recuit ulterieur en {alpha} du monocristal deforme sont etudiees suivant la nature des mecanismes de deformation. Dans le cas d'une deformation preponderante par glissement (010) [100], ou (011) [100], ou (110) [001], il y a recristallisation par 'croissance selective'. Si la deformation a lieu par bandes de deformation, il y a recristallisation par 'germination orientee'. Les cristaux deformes per maclage preponderant donnent par recristallisation des cristaux de dimensions maxima qui presentent des relations d'orientation etroites avec le cristal primitif. Enfin certains criteres d'ordre a la fois geometrique et dynamique sont discutes en vue d'expliquer l'apparition de tel ou tel mecanisme de deformation d'un monocristal d'orientation donnee. Cette etude, en conclusion, doit servir a definir les meilleures conditions (orientation cristalline et mode de deformation) qui permettraient la croissance de monocristaux parfaits de grandes dimensions. (auteur)}
place = {France}
year = {1960}
month = {Apr}
}