Neutron and heavy ion irradiations generally induce voids in metallic materials, and continuous radiations typically result in void swelling and mechanical failure of the irradiated materials. Recent experiments showed that nanovoids in nanotwinned copper could act as sinks for radiation-induced Frank loops, significantly mitigating radiation damage. In this paper, we report on structural evolution of Frank loops under cascades and address the role of nanovoids in absorbing Frank loops in detail by using molecular dynamics simulations. Results show that a stand-alone Frank loop is stable under cascades. When Frank loops are adjacent to nanovoids, the diffusion of a group of atoms from the loop into nanovoids is accomplished via the formation and propagation of dislocation loops. The loop–nanovoid interactions result in the shrinkage of the nanovoids and the Frank loops.
Bibliographical noteFunding Information:
Wang acknowledges the Start-up support by the University of Nebraska-Lincoln. Zhang acknowledges financial support by NSF-DMR-Metallic Materials and Nanostructures Program under Grant No. 1304101. Chen and Wang acknowledge the support provided by the US Department of Energy, Office of Science, Office of Basic Energy Sciences.