Positron annihilation lifetime measurement of electron irradiated Fe-Cr-Ni-P alloy

Fe-16%Cr-17%Ni-0.1%P alloy specimens were irradiated with 28 MeV electrons to a dose of 6.0×10²² e/m² at 77 K, and positron annihilation lifetime measurements were carried out to obtain the isochronal annealing behavior of radiation-induced defects above room temperature. A three-component analysis of lifetime spectra showed that a decrease in the second-component intensity I₂ occurred at about 373 K and 550 K, which is considered to be due to the disappearance of monovacancies by two different processes, namely, recombination with migrating self-interstitial atoms (373 K) and long-range migration of monovacancies to sinks (550 K). This latter stage is about 80K higher than the corresponding stage in Fe-13%Cr-14%Ni alloy specimen, which must be due to a vacancy-phosphorus interaction. The third component (microvoid component) intensity has a peak at about 373 K and disappears below 500 K.