Electron-irradiation induced defects in an Fe9Cr16Ni75 austenitic alloy

Austenitic Fe-16 wt% Cr-75 wt% Ni alloys have been investigated during 21 K electron irradiation and during subsequent isochronal anneals by electrical resistivity and positron lifetime measurements. The effect of silicon or titanium doping was determined, and the influence of nickel concentration was considered, on the basis of previously published results in the 20-45 wt% Ni range. With increasing nickel content, the following effects were observed. The Frenkel-pair resistivity, obtained from the initial damage-rates varied from 13.9 to 3.4 μΩcm/at%. During recovery anneals, the increases in resistivity, resulting from local atomic ordering induced by the long-range migration of point defects, were considerably amplified. Interstitial mobility increased progressively and the trapping efficiency of silicon for self-interstitials became smaller. By contrast, the mobility of vacancies was reduced in the 75% Ni alloys (it was concentration-independent up to 45% Ni) and their interactions with impurity atoms were decreased. (orig.)