The evolution of vacancy-type defects in Fe–Cr alloys (13–16at%Cr) undoped and doped with C, N, Au, or Sb and in conventional ferritic–martensitic steel (about 13%Cr) was investigated using positron annihilation spectroscopy under electron irradiation at room temperature and subsequent stepwise annealing. Small vacancy clusters were formed in the undoped Fe–16Cr alloy, which anneal out between 320 and 550K. It was shown that oversized substitutional solute atoms (Sb, Au) in the Fe–Cr alloy interact with vacancies and form complexes, which were stable up to 600 and 420K, respectively. It was found that the accumulation of vacancy defects considerably increased in the alloys and the steel with an enhanced content of interstitial impurities. It was shown that this effect was related to the formation of vacancy-carbon complexes. It was known that chromium in iron decreased the diffusion mobility of carbon. Therefore, the structure of vacancy-carbon complexes and the kinetics of their annealing in Fe–Cr alloys differ from those in the Fe–C system.

Effects of Solute Atoms on Evolution of Vacancy Defects in Electron-Irradiated Fe–Cr-Based Alloys. A.P.Druzhkov, A.L.Nikolaev: Journal of Nuclear Materials, 2011, 408[2], 194-200