Helium bubbles in Fe: equilibrium configurations and modification by radiation Xiao Gai Roger Smith Steven Kenny 2134/19684 https://repository.lboro.ac.uk/articles/journal_contribution/Helium_bubbles_in_Fe_equilibrium_configurations_and_modification_by_radiation/9234014 We have examined the properties of helium bubbles in Fe using two different Fe-He potentials. The atomic configurations and formation energies of different He-vacancy complexes are determined and their stability in the region of nearby collision cascades is investigated. The results show that the optimal He to Fe vacancy ratio increases from about 1:1 for approximately 5 vacancies up to about 4:1 for 36 vacancies. Collision cascades initiated near the complex show that Fe vacancies produced by the cascades readily become part of the He-vacancy complexes. The energy barrier for an isolated He interstitial to diffuse was found to be 0.06 eV. Thus a possible mechanism for He bubble growth would be the addition of vacancies during a radiation event followed by the subsequent accumulation of mobile He interstitials produced by the corresponding nuclear reaction. © 2013 Materials Research Society. 2015-11-30 14:17:15 He Radiation effects Fe Mathematical Sciences not elsewhere classified