Temperature effects on He bubbles production due to cascades in α-iron

The effects of irradiation temperature on the formation of He–vacancy clusters by displacement cascades in α-Fe are investigated by molecular dynamics (MD) methods. The irradiation temperatures of 100 and 600 K are considered for primary knock-on atom (PKA) energy, Ep, from 500 eV to 20 keV. The concentration of He in Fe varies from 1 to 5 at.%. We find that the number of Frenkel pairs (NF) at 600 K is slightly lower than that at 100 K for the same He concentration and Ep, but the number of He–vacancy clusters increases with increasing temperature for the same He concentration and energy recoils. However, the mean size of He–vacancy clusters is independent on temperature. The mechanisms of He bubble nucleation in displacement cascades at different temperatures are discussed in detail.