In-situ observation of an irradiation creep deformation mechanism in zirconium alloys

International audienceWe report an original experimental study on a zirconium alloy deformed in situ under ion irradiation and appliedstress inside a Transmission Electron Microscope. We observe that dislocations initially pinned on irradiation de-fects can be unpinned and glide at a lower stress under the effect of the irradiation. It is proposed that unpinningoccurs by a local effect of the displacement cascade created by the incoming ion in the vicinity of the pinningpoint. This novel mechanism of dislocation glide assisted by irradiation is thought to play a crucial role on in-reactor irradiation creep of zirconium alloys