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Influence des diinterstitiels sur les mesures de resistivite et du frottement interieur au cours de la precipitation dans des alliages fer-carbone
Vol.
7.
8, No.
7
ABSTRACTS OF ARTICLES TO APPEAR
xxxvii
INFLUENCE DES D I I N T E R S T I T I E L S SUR LES MESURES DE R E S I S T I V I T E , ET DU FROTTEMENT INTERIEUR AU COURS DE LA PRECIPITATION DANS DES ALLIAGES FER-CARBONE
the electronic part of the binding energy is a small part of ~Q, the difference between the activation energies for self-diffusion and impurity diffusion.
E. L. Mathe*, J. Parisot**, J. Santrot**, J. Grilhe* *Laboratoire de Metallurgie Physique L.A. 131 du C.N.R.S. 40, Avenue du Recteur Pineau 86022 Poitiers, France **Laboratoire de Mecanique et Physique Industrielle ENSMA, rue Guillaume VII le Troubadour 86000 Poitiers
9.
Received October 22, 1973 Revised March 22, 1974 Des experiences comparatives pr~cises sur la precipitation du carbone dans le fer a par mesures de r~sistivit~ ou de ~ottement int~rieur montrent que le d~calage observ~ n'est pas dfl ~ l'influence de differences de traitements thermiques. Ii pr~sente les m~mes variations au cours du temps que la concentration en paires d'atome d6duite des expressions de Damask. II semble pouvoir ~tre attribu~ aux di-interstitiels ~ i modifient la hauteur du pic de Snoek et contribuent ~ la r~sistivit~. II est sensiblement accru par une augmentation de la vitesse de trempe. 8.
IN ACTA MET
IMPURITY-VACANCY BINDING ENERGY IN TRANSITION METALS C. Demangeat Laboratoire de Structure Electronique des Solides (E.R.A. N°I00) Universite Louis Pasteur 4, rue Blaise Pascal 67000 Strasbourg, France Received March ii, 1974 Revised May 3, 1974
The impurity-vacancy binding energy is calculated using a tight binding scheme. The displaced charge is determined in the HartreeFock Slater approximation in order to take into account the presence of ferromagnetism at the end of the first transition series. Friedel's rule is introduced for selfconsistency up to the first nearest neighbours of the vacancy. A direct comparison with the experimental data is difficult but
DISCONTINUOUS REACTIONS IN ~uN ALUMINIUM-29 at.% ZINC ALLOY K. N. Melton & J. W. Edington Dept. of Metallurgy & Materials Science, University of Cambridge, Cambridge, England Received May 2, 1974
The characteristics of the nucleation and early stages of growth of discontinuous reactions at 250°C and 20°C have been determined for an aluminium-29at.% zinc alloy using transmission electron microscopy. At 250°C the grain boundary migrated producing lamellae of aluminium and zinc rich phases. In contrast at 20°C the grain boundary remained essentially stationary while on both sides a granular morphology of the two phases was produced. There was no detectable misorientation at the interface between the granular region and the untransformed grain. It is suggested that the differences in behaviour at the two temperatures is a consequence of changes in boundary mobility. The most likely mechanism for the low temperature reaction appears to be autocatalytic nucleation on dislocations punched out by the zinc rich phase. I0.
CINETIQUE DE PRECIPITATION DES LACUNES LORS DE LA FORMATION DES TETRAEDRES DE FAUTE D' EMPILEMENT DANS L'OR TREMPE G.Moya Laboratoire de MetallurgieCentre de Saint Jerome 13397 Marseille Cedex 4 France Adresse actuelle: Institut des Sciences BP 1027 N'Djamena Republique du Tchad Received April
8, 1974
On a ~tudie par calorim~trie la cinEtique de precipitation des lacunes dans l'or tremp~ lorsqu'il y a formation de tEtra~dres de faute d'empilement. Les ~chantillons tremp~s partir de 900°C subissent un revenu l'int~rieur d'un microcalorim~tre diffErentiel ~ conduction.
7.
8, No.
7
ABSTRACTS OF ARTICLES TO APPEAR
xxxvii
INFLUENCE DES D I I N T E R S T I T I E L S SUR LES MESURES DE R E S I S T I V I T E , ET DU FROTTEMENT INTERIEUR AU COURS DE LA PRECIPITATION DANS DES ALLIAGES FER-CARBONE
the electronic part of the binding energy is a small part of ~Q, the difference between the activation energies for self-diffusion and impurity diffusion.
E. L. Mathe*, J. Parisot**, J. Santrot**, J. Grilhe* *Laboratoire de Metallurgie Physique L.A. 131 du C.N.R.S. 40, Avenue du Recteur Pineau 86022 Poitiers, France **Laboratoire de Mecanique et Physique Industrielle ENSMA, rue Guillaume VII le Troubadour 86000 Poitiers
9.
Received October 22, 1973 Revised March 22, 1974 Des experiences comparatives pr~cises sur la precipitation du carbone dans le fer a par mesures de r~sistivit~ ou de ~ottement int~rieur montrent que le d~calage observ~ n'est pas dfl ~ l'influence de differences de traitements thermiques. Ii pr~sente les m~mes variations au cours du temps que la concentration en paires d'atome d6duite des expressions de Damask. II semble pouvoir ~tre attribu~ aux di-interstitiels ~ i modifient la hauteur du pic de Snoek et contribuent ~ la r~sistivit~. II est sensiblement accru par une augmentation de la vitesse de trempe. 8.
IN ACTA MET
IMPURITY-VACANCY BINDING ENERGY IN TRANSITION METALS C. Demangeat Laboratoire de Structure Electronique des Solides (E.R.A. N°I00) Universite Louis Pasteur 4, rue Blaise Pascal 67000 Strasbourg, France Received March ii, 1974 Revised May 3, 1974
The impurity-vacancy binding energy is calculated using a tight binding scheme. The displaced charge is determined in the HartreeFock Slater approximation in order to take into account the presence of ferromagnetism at the end of the first transition series. Friedel's rule is introduced for selfconsistency up to the first nearest neighbours of the vacancy. A direct comparison with the experimental data is difficult but
DISCONTINUOUS REACTIONS IN ~uN ALUMINIUM-29 at.% ZINC ALLOY K. N. Melton & J. W. Edington Dept. of Metallurgy & Materials Science, University of Cambridge, Cambridge, England Received May 2, 1974
The characteristics of the nucleation and early stages of growth of discontinuous reactions at 250°C and 20°C have been determined for an aluminium-29at.% zinc alloy using transmission electron microscopy. At 250°C the grain boundary migrated producing lamellae of aluminium and zinc rich phases. In contrast at 20°C the grain boundary remained essentially stationary while on both sides a granular morphology of the two phases was produced. There was no detectable misorientation at the interface between the granular region and the untransformed grain. It is suggested that the differences in behaviour at the two temperatures is a consequence of changes in boundary mobility. The most likely mechanism for the low temperature reaction appears to be autocatalytic nucleation on dislocations punched out by the zinc rich phase. I0.
CINETIQUE DE PRECIPITATION DES LACUNES LORS DE LA FORMATION DES TETRAEDRES DE FAUTE D' EMPILEMENT DANS L'OR TREMPE G.Moya Laboratoire de MetallurgieCentre de Saint Jerome 13397 Marseille Cedex 4 France Adresse actuelle: Institut des Sciences BP 1027 N'Djamena Republique du Tchad Received April
8, 1974
On a ~tudie par calorim~trie la cinEtique de precipitation des lacunes dans l'or tremp~ lorsqu'il y a formation de tEtra~dres de faute d'empilement. Les ~chantillons tremp~s partir de 900°C subissent un revenu l'int~rieur d'un microcalorim~tre diffErentiel ~ conduction.