The defect production and annealing in pure Fe-17Cr-14Ni (17–14), Fe-16Cr-25Ni (16–25) alloys and in alloys doped with Sc, irradiated with 30-MeV electrons at 4.2 K, were studied via measurements of residual electric resistivity and magnetic resistivity.
The dose dependence of electric resistivity behavior indicated that in each case the heat treatment and doping have no effect on defect production. The derived values of electric resistivity per Frenkel pair(ρF) were 14.5 μΩcm/at%for 17–14 and 12.8 μΩ cm/at%for 16–25.
The recovery of irradiation-induced electric resistivity (Δρ/Δρ0) in the temperature range from 4.2 to 800 K in each case was nonmonotonous. The self-interstitial migration energy was found to rise from 0.92 to 1.03 eV as the weight percent concentrations of nickel decreased from 25 to 14. The vacancy migration energy in both cases was ≃ 1.2 eV. Sc doping to 16–25 does not affect the mobility of self-interstitials while raising the vacancy migration energy by 0.1 eV.
It was found that Sc atoms retard the defect anneal in the temperature range from 200 to 600 K. The alloy composition has been found to be dependent on impurity atom interactions with defects. We demonstrate that for the 17–14 (Sc) alloy the short-range atomic ordering in the vacancy mobility temperature region (T > 300 K) is associated with the local concentration growth of atomic Fe-Fe pairs.
The present results and the observed behavior of electric resistivity variations in unirradiated alloys prompt this conclusion about the formation of Sc-vacancy complexes, whose thermal stability depends on the Ni content in the alloy.