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

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 II and, mainly, vacancy migration in stage III. 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. (author)