Atomistic simulations of the formation of < c >-component dislocation loops in alpha-zirconium

C Dai and L Balogh and ZW Yao and MR Daymond, JOURNAL OF NUCLEAR MATERIALS, 478, 125-134 (2016).

DOI: 10.1016/j.jnucmat.2016.06.002

The formation of -component dislocation loops in alpha-Zr is believed to be responsible for the breakaway irradiation growth experimentally observed under high irradiation fluences. However, while -loop growth is well described by existing models, the atomic mechanisms responsible for the nucleation of -component dislocation loops are still not clear. In the present work, both interstitial and vacancy -type dislocation loops are initially equilibrated at different temperatures. Cascades simulations in the vicinity of the -type loops are then performed by selecting an atom as the primary knock-on atoms (PKAs) with different kinetic energies, using molecular dynamics simulations. No -component dislocation loop was formed in cascades simulations with a 10 keV PKA, but -component interstitial loops were observed after the interaction between discontinuous 50 keV PKAs and preexisting -type interstitial loops. The comparisons of cascades simulations in volumes having preexisting -type interstitial and vacancy loops suggest that the reaction between the PKAs and -type interstitial loops is responsible for the formation of -component interstitial loops. (C) 2016 Elsevier B.V. All rights reserved.

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