Recovery of He, H and D implanted Ta, Nb, W and AISI 316L steel samples in annealing

The annealing behaviour of Ta, Nb, W and AISI 316L stainless steel samples implanted with 20 keV helium ions and either with 15 keV hydrogen or 12 keV deuterium ions was studied. By observing the release of trapped hydrogen and deuterium, it was concluded that the helium associated hydrogen trapping defects recover at a temperature of 488 K in steel, 583 K in W, 648 K in Ta, and 553 K in Nb. The observed recovery temperatures of hydrogen irradiation induced traps are lower than the recovery temperatures of traps trapping solid soluble hydrogen migrating from the metal bulk after the helium implantation, deduced in an earlier study [P. Haussalo, J. Keinonen, U.-M. Jaske, and J. Sievinen, J. Appl. Phys. 75, 7770 (1994)]. This indicates that the hydrogen implantation changes the characteristics of the helium associated defects. The proposed trapping mechanism is binding at the surface of helium bubbles, as suggested in the above mentioned study, affected by the properties of the ion-implantation induced damage.