Degradation of mechanical properties due to nanometric irradiation induced defects was one of the challenging issues in designing materials for future fusion reactors. Various types of defects such as voids and He bubbles may be produced due to high dose of neutron irradiation due to fusion reaction. The influence of He bubble on the mobility of an edge dislocation in pure body-centered cubic Fe was studied using molecular dynamics simulation as a function of bubble size, He density and temperature. It appears that low contents He bubbles were penetrable defects, which size and temperature rise make them harder and softer, respectively. At high He contents a size dependent loop punching was observed, which at larger bubble sizes leads to a multistep dislocation-defect interaction. It also appears that the bubble surface curvature and temperature were the main parameters in the screw segments annihilation needed for the release of the dislocation from the bubble.

Atomistic Simulation of He Bubble in Fe as Obstacle to Dislocation. S.M.H.Haghighat, G.Lucas, R.Schäublin: IOP Conference Series - Materials Science and Engineering, 2009, 3[1], 012013