A study of the point-defect mobility in Ag-Cu by high-voltage electron microscopy

A study is carried out by high-voltage electron microscopy on the relative mobility of interstitials and vacancies in an Ag-0.17 at% Cu alloy in the temperature range of 300 to 775 K. Shortly after starting the irradiation stacking-fault tetrahedra are formed in the whole range of temperatures investigated. This indicates that the mobility of vacancies is higher than that of self-interstitials. This can be explained by the formation of interstitial-solute complexes retarding interstitial motion. During further irradiation solute segregation occurs to point-defect sinks with the result that the interstitial mobility increases to the extent that it eventually surpasses that of the vacancies. (author)