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Tensile deformations in mono- and polycrystalline uranium between 20 deg. C and -196 deg. C; Deformation par traction de l'uranium mono- et polycristallin entre 20 deg. C et -196 deg. C

Abstract

Tensile stress tests been carried out at low temperatures (between 20 C and -196 C) on monocrystalline and polycrystalline uranium of various purities. The mechanical properties of the monocrystals have been related, at all temperatures, to plastic flow mechanisms. Below -100 C brittle fracture occurs on the planes making up the twins. A detailed study of the plastic behaviour at -196 C has made it possible to show that all the twin planes except the [176] plane were liable to become privileged planes for brittle fracture. The mechanical properties of the polycrystals, the breaking stress and the elongation at breaking point, decrease as the temperature decreases from 20 to -196 C; they undergo a transition however - not to be confused with the ductile-brittle transition - whose position and strength depend on the grain size and on the purity. It has been verified also that Petch's law is approximately applicable to the plastic flow and rupture stresses; a study has also been made of the influence of temperature and purity on the constants occurring in this equation. Finally, experiments at -196 C on the deformation up to breaking point of polycrystalline samples cold-worked at 20 C have shown the importance  More>>
Authors:
Lemogne, A [1] 
  1. Commissariat a l'Energie Atomique, Saclay (France). Centre d'Etudes Nucleaires
Publication Date:
Jun 01, 1965
Product Type:
Thesis/Dissertation
Report Number:
CEA-R-2819
Resource Relation:
Other Information: 71 refs
Subject:
36 MATERIALS SCIENCE; CRYSTAL STRUCTURE; DUCTILE-BRITTLE TRANSITIONS; ELONGATION; FRACTURE PROPERTIES; MECHANICAL TESTS; MICROSTRUCTURE; RUPTURES; TEMPERATURE DEPENDENCE; TENSILE PROPERTIES; TWINNING; URANIUM
OSTI ID:
20650660
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: FR05R2819090273
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
[75] pages
Announcement Date:
Nov 23, 2005

Citation Formats

Lemogne, A. Tensile deformations in mono- and polycrystalline uranium between 20 deg. C and -196 deg. C; Deformation par traction de l'uranium mono- et polycristallin entre 20 deg. C et -196 deg. C. France: N. p., 1965. Web.
Lemogne, A. Tensile deformations in mono- and polycrystalline uranium between 20 deg. C and -196 deg. C; Deformation par traction de l'uranium mono- et polycristallin entre 20 deg. C et -196 deg. C. France.
Lemogne, A. 1965. "Tensile deformations in mono- and polycrystalline uranium between 20 deg. C and -196 deg. C; Deformation par traction de l'uranium mono- et polycristallin entre 20 deg. C et -196 deg. C." France.
@misc{etde_20650660,
title = {Tensile deformations in mono- and polycrystalline uranium between 20 deg. C and -196 deg. C; Deformation par traction de l'uranium mono- et polycristallin entre 20 deg. C et -196 deg. C}
author = {Lemogne, A}
abstractNote = {Tensile stress tests been carried out at low temperatures (between 20 C and -196 C) on monocrystalline and polycrystalline uranium of various purities. The mechanical properties of the monocrystals have been related, at all temperatures, to plastic flow mechanisms. Below -100 C brittle fracture occurs on the planes making up the twins. A detailed study of the plastic behaviour at -196 C has made it possible to show that all the twin planes except the [176] plane were liable to become privileged planes for brittle fracture. The mechanical properties of the polycrystals, the breaking stress and the elongation at breaking point, decrease as the temperature decreases from 20 to -196 C; they undergo a transition however - not to be confused with the ductile-brittle transition - whose position and strength depend on the grain size and on the purity. It has been verified also that Petch's law is approximately applicable to the plastic flow and rupture stresses; a study has also been made of the influence of temperature and purity on the constants occurring in this equation. Finally, experiments at -196 C on the deformation up to breaking point of polycrystalline samples cold-worked at 20 C have shown the importance of the role played by intergranular cracks in the plastic behaviour of uranium. (author) [French] Des essais de traction ont ete realises a basse temperature (entre 20 C et -196 C, sur des monocristaux et des polycristaux d'uranium de differentes puretes. Les proprietes mecaniques des monocristaux ont ete reliees, a toutes temperatures, aux mecanismes d'ecoulement plastique. Une rupture fragile intervient a partir de -100 C sur les plans de composition de macle. L'etude detaillee du comportement plastique a -196 C a permis de preciser que tous les plans de macle, sauf [176], etaient susceptibles de devenir des plans de rupture fragile privilegies. Les proprietes mecaniques des polycristaux, contrainte de rupture et allongement a la rupture, decroissent quand on abaisse le temperature de 20 a -196 C, mais marquent une transition - a distinguer de la transition ductile-fragile - dont la position et l'intensite dependent de la grosseur du grain et de la purete. Il a ete verifie, par ailleurs, que la loi de Petch s'appliquait avec une bonne approximation aux contraintes d'ecoulement plastique et de rupture; l'influence de la temperature et de la purete sur les constantes de cette loi a ete egalement etudiee. Enfin, des experiences portant sur la deformation jusqu'a rupture a -196 C d'eprouvettes polycristallines pre-ecrouies a 20 C, ont revele l'importance du role joue par la fissuration intergranulaire dans le comportement plastique de l'uranium. (auteur)}
place = {France}
year = {1965}
month = {Jun}
}