Single and multiple trapping of radiation-induced defects in AgZn alloys

Abstract

1984) Single and multiple trapping of radiation-induced defects in AgZn alloys, Radiation Effects, 82:1-2, 141-153, Experimental results on the recovery spectra of low temperature electron irradiated pure Ag and AgZn alloys in the concentration range 0.018 to 30 at.% of zinc are presented. Their comparison leads to consider two distinct concentration domains. In the low concentration domain the classical model of Corbett, Smith and Walker applies with some modifications. The resistivity recovery is governed by the combinations and annihilations of point defects. It must be noted that even in dilute alloys, new kinds of point defects (such as mixed interstitials) arise from the presence of solute atoms. In the high concentration domain, the resistivity recovery is dominated by the setting in of short-range order as a result of the point defect migration: interstitial migration in stage I1 and, mainly, vacancy migration in stage 111. The defect migration, free in the pure metal, is influenced, in the concentrated alloys, by the local environment. The proposed model consistently allows the interpretation of the existing results, particularly from electron microscopy.Nous presentons des spectres d'evolution de la resistivite electrique obtenus lors de recuits apres irradiation electronique a basse temperature, dans I'argent pur et dans des alliages AgZn dont la concentration varie de 0,018 a 30% at. de zinc. La comparaison des resultats amkne a considerer deux domaines de concentration. Dans le domaine des faibles concentrations, le modele classique de Corbett, Smith et Walker avec quelques modifications explique bien ces spectres. Le recuit de la resistivitk est regi par les combinaisons et annihilations des defauts ponctuels. II importe de ne pas perdre de vue que la presence d'impuretts m&me en faible concentration peut induire de nouvelles expkces de defauts (interstitiels mixtes, par exemple). Aux concentrations plus elevies, le recuit de la resistivite est domine par la mise en ordre a courte distance qui resulte de la migration des defauts; interstitiels dans I'etape I1 et, surtout, lacunes dans I'etape 111. La migration des defauts, libre dans le mCtal pur ou les alliages dilues, est influencCe par I'environnement local dans le cas des alliages concentrks. Le modele propose permet une interpretation cohCrente des rtsultats existants, en particulier de microscopie electronique. ?Permanent address : Ecole Nationale Superieure de Ceramique Industrielle, 47, rue Albert Thomas, F-87100 Limoges, France. 141 Downloaded by [Michigan State University] at 00:21 05 February 2015 142 F. M A U R Y el tit. I INTRODUCTIONUsing a strain relaxation method Halbwachs and Hillairet have shown that in the electron irradiated alloy Ag-30 at. % Zn, the vacancies are more mobile than the interstitial defects in a wide temperature range around and above room temperature.','! By high voltage electron microscopy, Halbwachs and Yoshida3 reached a similar conclusion in the more dilute Ag-9 at.% Zn provided the temperature was lower than ...

Specificity of stage III in electron-irradiated Fe-Cr alloys

“…A similar situation is known in FCC alloys and the related references have been mentioned in the paper [19][20][21]. The only specificity of our case is very close positions of the onsets of long-range migration for vacancies and IAs, which, as has been shown above, creates grounds for confusion of them both.…”

“…Four other samples (Cr4-2, Cr4-3 and Cr9-2, Cr9-3) were irradiated (5 MeV electrons, LINAC) to a significantly higher dose and annealed together in another run (run 19). In this run, the irradiation procedure [11,14] was modified.…”

“…In pure metals the onsets of free migration for both IAs and vacancies are observed. It is known that the IA migration in concentrated alloys, including Fe-Cr, can be strongly modified, giving evidence for configuration trapping [10,11,[18][19][20][21], and therefore, only the onset of free migration of vacancies may be available for observation, as compared to pure metals. These two onset types of long-range defect migration demonstrate different behaviour with change in the defect concentration (or Á 0 ).…”

Stage I of recovery in 5 MeV electron-irradiated iron and iron-chromium alloys: the effect of small cascades, migration of di-interstitials and mixed dumbbells

“…Recently these results have been reproduced in Fe-Cr alloys [3]. IA trapping in configurations including several Cr atoms (configuration trapping) has also been reported [1] in concentrated Fe-Cr alloys, similar to the phenomenon observed earlier in FCC Ag-Zn alloys [4]. Since such trapping can modify significantly the properties of IAs [4,5], it may be one of the physical mechanisms leading to the swelling resistance of Fe-Cr alloys, and it therefore requires detailed investigation.…”

Μελέτη βλαβών που προκαλούνται από ακτινοβόληση με πρωτόνια σε κράματα Fe-Cr με μετρήσεις ηλεκτρικής αντίστασης

“…Τα φα σματα αποκατα στασης πυκνω ν κραμα των μετα απο ακτινοβο ληση σε χαμηλε ς θερμοκρασι ες περιπλε κονται απο τις αλλαγε ς που επιφε ρει η ακτινοβο ληση στην ατομικη τα ξη. Αυτο ε χει παρατηρηθει σε δια φορα δυαδικα κρα ματα (Maury et al, 1984;Dimitrov and Dimitrov, 1984;Vaessen et al, 1984) αλλα σχετικε ς ενδει ξεις υπα ρχουν και για τα κρα ματα Fe-Cr στις εργασι ες των Nikolaev et al (1997) και Benkaddour et al (1987).…”