Simulations of reactions between irradiation induced 〈a〉-loops and mixed dislocation lines in zirconium

The interaction between mixed dislocations gliding in the basal plane with elliptical prism plane vacancy loops characteristic of irradiation induce loops is studied using Molecular Dynamics simulations. A methodology to create elliptical loops in the prism plane with major axes in the [0001] direction and with Burgers vectors in the [1¯21¯0] direction is described. Dislocation reactions involving mixed dislocations, parallel to [1¯21¯0] with a Burgers vector of a/3[2¯110] and gliding in the basal plane in the [101¯0] direction are investigated. The reaction of the mixed dislocation and vacancy loops in prism planes (1¯100) or (1¯010) and with Burgers vector a/3[1¯21¯0] leads to the creation of two jogs in the vacancy loop. These loops present a significant barrier to the motion of the mixed dislocation gliding in the basal plane. The reaction of the mixed dislocation and a vacancy loop in the (101¯0) prism plane with Burgers vector a/3[2¯110] leads to the cleaving of the vacancy loop and the absorption of part of the vacancy loop into the gliding dislocation. This loop presents a relatively weaker barrier to the motion of the mixed dislocation gliding in the basal plane. Strain rate is observed to have a large impact on the shear stress-displacement behavior of the reactions, but not on the reaction mechanisms.