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Study of uranium-titanium diffusion; Etude de la diffusion uranium-titane

Abstract

In the overall scheme of research on the chemical diffusion of uranium and the transition metals we have studied the uranium-titanium system. The diffusion couples are prepared by welding together small plates of uranium and titanium under pressure, using a technique already described by us. After diffusion under vacuum, polished sections of the samples were micro-graphically examined. This inspection showed that intergranular diffusion occurred at temperatures below 650 deg. C. At higher temperatures, the diffusion occurred uniquely throughout the volume of the metal, and the diffusion zone appeared as a succession of micro-graphically distinguishable bands. Study of the rate of increase of these corresponding 'penetration coefficients'. In addition, we have observed important variations in microhardness within the diffusion zone, we have tried to relate these variations to the variation of concentration. This is measured with the Castaing microprobe. We have thus accurately established the concentration-penetration curves for temperatures between 950 and 1075 deg. C. From these curves, we have calculated the diffusion coefficient D as a function of the concentration using Matano's method. At all temperatures, D(c) curve has a U form as for the U-Zr system. The activation energy has a maximum value of 42 kcal/g atom at an  More>>
Authors:
Adda, Y; Philibert, J; [1]  Institut de Recherches de la Siderurgie Francaise (IRSID), 78 - Saint-Germain-en-Laye (France)]
  1. Commissariat a l'Energie Atomique, Saclay (France).Centre d'Etudes Nucleaires
Publication Date:
Jul 01, 1959
Product Type:
Technical Report
Report Number:
CEA-R-1297
Resource Relation:
Conference: Symposium on Solid State Diffusion, Colloque sur la diffusion a l'etat solide, Saclay (France), 3-5 Jul 1958; Other Information: 8 refs
Subject:
36 MATERIALS SCIENCE; ACTIVATION ENERGY; ATOM TRANSPORT; COMPARATIVE EVALUATIONS; DIFFUSION; KIRKENDALL EFFECT; MICROHARDNESS; PHOTOMICROGRAPHY; POROSITY; SAMPLE PREPARATION; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 1000-4000 K; TIME DEPENDENCE; TITANIUM; URANIUM; VACANCIES; ZIRCONIUM
OSTI ID:
20940775
Research Organizations:
CEA Saclay, 91 - Gif-sur-Yvette (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR07R1297094253
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
7 pages
Announcement Date:
Nov 26, 2007

Citation Formats

Adda, Y, Philibert, J, and Institut de Recherches de la Siderurgie Francaise (IRSID), 78 - Saint-Germain-en-Laye (France)]. Study of uranium-titanium diffusion; Etude de la diffusion uranium-titane. France: N. p., 1959. Web.
Adda, Y, Philibert, J, & Institut de Recherches de la Siderurgie Francaise (IRSID), 78 - Saint-Germain-en-Laye (France)]. Study of uranium-titanium diffusion; Etude de la diffusion uranium-titane. France.
Adda, Y, Philibert, J, and Institut de Recherches de la Siderurgie Francaise (IRSID), 78 - Saint-Germain-en-Laye (France)]. 1959. "Study of uranium-titanium diffusion; Etude de la diffusion uranium-titane." France.
@misc{etde_20940775,
title = {Study of uranium-titanium diffusion; Etude de la diffusion uranium-titane}
author = {Adda, Y, Philibert, J, and Institut de Recherches de la Siderurgie Francaise (IRSID), 78 - Saint-Germain-en-Laye (France)]}
abstractNote = {In the overall scheme of research on the chemical diffusion of uranium and the transition metals we have studied the uranium-titanium system. The diffusion couples are prepared by welding together small plates of uranium and titanium under pressure, using a technique already described by us. After diffusion under vacuum, polished sections of the samples were micro-graphically examined. This inspection showed that intergranular diffusion occurred at temperatures below 650 deg. C. At higher temperatures, the diffusion occurred uniquely throughout the volume of the metal, and the diffusion zone appeared as a succession of micro-graphically distinguishable bands. Study of the rate of increase of these corresponding 'penetration coefficients'. In addition, we have observed important variations in microhardness within the diffusion zone, we have tried to relate these variations to the variation of concentration. This is measured with the Castaing microprobe. We have thus accurately established the concentration-penetration curves for temperatures between 950 and 1075 deg. C. From these curves, we have calculated the diffusion coefficient D as a function of the concentration using Matano's method. At all temperatures, D(c) curve has a U form as for the U-Zr system. The activation energy has a maximum value of 42 kcal/g atom at an atomic concentration of 0,5. Even though we have rarely seen pores in the diffusion zone, we have nevertheless observed an important Kirkendall-effect by studying the displacements x{sub i} of the interface using tungsten wires as markers. These displacements can be expressed as a function of time and temperature by the equation: x{sub i} = 0,9 t {sup 1/2} exp ( - 14600/(RT)). Finally, using Darken's equations we calculated the intrinsic diffusion coefficients Du and Dti as well as the corresponding activation energies. These energies are similar (QU = 38,5 and QTi = 40 kcal/at. g) and also almost the same as those found for the U-Zr system. (author) [French] Dans le cadre de recherches sur la diffusion chimique de l'uranium et des metaux de transition, nous avons etudie le systeme uranium-titane. Les couples de diffusion sont prepares, suivant une technique que avons deja decrite, par soudage sous pression de plaquettes d'uranium et de titane. Apres traitement de diffusion sous vide, les echantillons sont etudies micrographiquement suivant une section polie. Cet examen nous a permis de mettre en evidence une diffusion intergranulaire au-dessous de 650 deg. C; aux temperatures superieures, la diffusion a lieu uniquement en volume, et la zone de diffusion apparait alors comme une succession de bandes qui se distinguent par leur aspect micrographique. L'etude de la cinetique de croissance de ces bandes nous a permis de mesurer les 'coefficients de penetration' correspondants. En outre, nous avons observe, dans la zone de diffusion, des variations importantes de microdurete, que nous avons cherche a relier a la variation de concentration. Celle-ci est mesuree par analyse ponctuelle au moyen de la microsonde de Castaing. Nous avons ainsi etabli avec precision les courbes concentration-penetration pour des temperatures comprises entre 950 et 1075 deg. C. A partir de ces courbes nous avons calcule le coefficient de diffusion D en fonction de la concentration c par la methode de Matano. La coube D(c) presente a toutes les temperatures une forme en U, deja observee pour le systeme U-Zr. L'energie d'activation passe par un maximum de 42 kcal/g pour une concentration atomique 0,5. Bien que nous n'ayons observe que rarement la presence de pores dans la zone de diffusion, nous avons neanmoins observe un effet Kirkendall important en etudiant les deplacements x{sub i} d'un interface repere au moyen de fils de tungstene. Ces deplacements peuvent s'exprimer en fonction du temps t et de la temperature T par la relation x{sub i} = 0,9 t {sup 1/2} exp ( - 14600/(RT)). Enfin, au moyen des equations de Darken nous avons calcule les coefficients de diffusion intrinseques DU et DTi, ainsi que les energies d'activations correspondantes: ces dernieres sont tres voisines et egalement proches de celles que nous avions calculees dans le cas du couple U-Zr (Qu = 38,5 et Qti = 40 kcal/ at. g). (auteur)}
place = {France}
year = {1959}
month = {Jul}
}