A novel displacement cascade driven irradiation creep mechanism in α-zirconium: A molecular dynamics study

In-situ TEM irradiation creep experiment revealing radiation induced dislocation glide in pure copper

“…However, the climb based mechanisms only concern edge dislocations, and do not apply to the screw dislocations observed in our experiments. Very recently, Khiara et al [43] showed through molecular dynamics simulations performed on pure zirconium and for stresses just below the yield stress, the release of screw dislocations pinned on small loops by displacement cascades generated by irradiation. After the unpinning of the dislocation, it was observed that the freed dislocation is now straight and that the loop is partially destructed.…”

A molecular dynamics study of a cascade induced irradiation creep mechanism in pure copper

“…The methodology is similar to the one used for zirconium in our previous MD study [26]. First, a molecular dynamics simulation box containing a screw dislocation and a Frank loop is generated using NUMODIS [29,30,31].…”

“…In a previous study, we [26] investigated the effect of a cascade on a screw dislocation pinned on a loop at high applied stress in zirconium using MD simulations to reproduce similar configurations as in the TEM in-situ straining experiments of Gaumé et al [9] on a zirconium alloy. A possible unpinning of dislocations by cascades was predicted at high stress levels slightly inferior to the critical stress for unpinning (without a cascade).…”

“…In these simulations, the generated cascades had to encompass the pinning points of dislocations to induce unpinning, and we developed a simple closed-form model to account for this phenomenon. Based on this closed-form model, we [26] estimated the mean pinning lifetime in the conditions of the experiments of Gaumé et al [9] and obtained pinning lifetimes at high stress levels in the same orders of magnitude as the experimental pinning lifetime.…”

Inversion of dislocation loop nature driven by cluster migration in self-ion irradiated nickel

“…1(e)) outside the damage profile. A plausible explanation is that the migration of clusters and loops (created in irradiated zones) is enhanced by cascade damage [39]. Once they move into unirradiated zones, their mobility reduces strongly so the majority remain at this depth leading to the loop agglomeration.…”