Structure of dislocations in Al and Fe as studied by positron-annihilation spectroscopy

C. Hidalgo, G. González-Doncel, S. Linderoth, and J. San Juan
Phys. Rev. B 45, 7017 – Published 1 April 1992
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Abstract

Positron-lifetime-spectra measurements have been performed on single crystals of Al and polycrystals of Fe deformed under the tensile mode at room temperature and 77 K, respectively. It is shown that the positron-trapping component in Al depends on the number of slip systems activated: The positron lifetime is 215, 220, and 240 ps when single-, double-, and multiple-slip planes are activated, respectively. This dependence is well understood if positrons annihilate at dislocation-associated defects (jogs) with different positron-annihilation characteristics revealing different jog structures. In iron, the positron-lifetime spectra associated with dislocations were found to be independent of the annealing temperature between 110 and 360 K. In this temperature range, screw dislocations should transform into nonscrew dislocations, suggesting that the positrons are not sensitive to the different types of dislocations. These results are interpreted on the basis that positrons annihilate at defects associated with the dislocations rather than at the dislocation lines.

  • Received 22 March 1991

DOI:https://doi.org/10.1103/PhysRevB.45.7017

©1992 American Physical Society

Authors & Affiliations

C. Hidalgo

  • Asociación EURATOM/CIEMAT, Avenida Complutense 22, 28040 Madrid, Spain

G. González-Doncel

  • Centro Nacional de Investigaciones Metalúrgicas, Consejo Superior de Investigaciones Científicas, Avenida de Gregorio del Amo 8, 28040 Madrid, Spain

S. Linderoth

  • Laboratory of Applied Physics, Technical University of Denmark, 2800 Lyngby, Denmark

J. San Juan

  • Departamento de Física de la Materia Condensada, Facultad de Ciencias, Universidad del País Vasco, Apartado 644, 48080 Bilbao, Spain

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Vol. 45, Iss. 13 — 1 April 1992

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