Phase and structural transformations in metallic iron under the action of heavy ions and recoil nuclei

By the use of various modes of Mössbauer spectroscopy after effects of irradiation of metal iron with 12C4+ and 14N5+ ions of medium energies, and alpha-particles and the 208Tl, 208,212Pb, and 216Po recoil from a 228Th-source have been studied. The experimental data obtained in the study enabled various types of external and internal radiation to be compared in regard to the damage they cause, as well as to their effect on the structure-, phase composition- and corrosion resistance properties of metallic iron. Irradiation with 12C4+ and 14N5+ ions is accompanied by both structural disordering of the α-Fe lattice, and the appearance of γ-phase in the bulk metal. This is indicated by a single line which is 2 to 3-fold broadened (as compared to the lines of the magnetic sextet). This is a result of a strong local heating of the lattice in the thermal spike area with a subsequent instant cooling-down and recrystallization of this “molted” area. Irradiation of iron foils with 12C4+- and 14N5+ ions and with recoil nuclei does provoke corrosion processes (the formation of γ-FeOOH) and is accompanied by an intensive oxidation of the metal.