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SECONDARY DEFECTS IN QUENCHED ALUMINIUM STUDIED BY MOSSBAUER SPECTROSCOPY

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HAL Id: jpa-00216717

https://hal.archives-ouvertes.fr/jpa-00216717

Submitted on 1 Jan 1976

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SECONDARY DEFECTS IN QUENCHED

ALUMINIUM STUDIED BY MOSSBAUER

SPECTROSCOPY

Chr. Janot, H. Georges-Gibert

To cite this version:

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JOURNAL DE PHYSIQUE Colloque C6, suppltment au no 12, Tome 37, Dtcembre 1976, page C6-903

SECONDARY DEFECTS IN QUENCHED ALUMINIUM

STUDIED BY

MOSSBAUER SPECTROSCOPY

(*)

Chr. JANOT and H. GEORGES-GIBERT

Laboratoire de Physique du Solide, Case Officielle no 140, 54037 Nancy Cedex, France

Rbum6. - Le facteur Debye-Waller, le deplacement isomMque et I'effet Doppler du second ordre ont &tB mesures dans un alliage dilue &Fe trempe contenant 200 ppm de 57Fe, aprbs des traitements thermiques a des temperatures comprises entre 78 et 623 K. La monotonie de variation des parambtres Mossbauer est perturbee par une brusque variation pour des recuits autour de 260 K, cette temperature variant avec la vitesse de trempe et I'histoire thermique de 1'Cchantillon. Cette brusque variation est interpretbe en supposant que des lacunes viennent se pieger sur les impuretes de fer, Bvoluent ensuite en amas puis en boucle de dislocation, pour conduire au stade initial de la precipitation. La variation d'ensemble des parambtres Mossbauer met en kvidence l'existence de transfert electronique 3d -+ S en fonction de la tempkrature.

Abstract. - We measured the Debye-Waller factor, the isomer shift and the second-order Doppler effect in a quenched aluminium based alloy containing 200 ppm of 57Fe, after an annealing treatment up to temperatures ranging from 78 to 623 K. A discontinuity in the smooth variations of the Mossbauer parameters appeared for samples annealed at temperatures around 260 K, which depends on the quenching rate and the thermal history of the specimen. This discontinuity was interpreted both in terms of vacancies trapped at 57Fe impurities and the subsequent agglo- meration process, and of annealing of the dislocation loops up to the initial stage of the precipitation of the iron. Supplementary investigations of the overall variations of the Mossbauer parameters led to information on the 3d

-.

S electron transfer process related to the isomer shift temperature dependence.

(*) This paper is part of H. Georges-Gibert's doctoral thesis.

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