MD simulation of the behavior of small dislocation loops in irradiated metal during deformation

In this study, MD simulations of compression process were carried for copper lattices with an interstitial type Frank loops. Slipping of prismatic dislocations was not observed for loops whose size ranges from 0.5nm to 3.6nm. For loops with a size of 0.5nm, atoms in loops were squeezed into the neighboring layer to form crowdion bundles along <110> directions, and then swept away by further deformation. For loops larger than 2nm, the movements of atoms in faulted layer were not homogeneously in one direction during elastic deformation process, its extrinsic stacking was broken into two intrinsic ones exist on two successive planes. After yielding the slipping on these two successive planes accommodated the plastic deformation and broke up the loop. The results in this work proved that, for low stacking fault energy FCC metals such as copper and stainless steel, to describe the their deformation mechanism after neutron or heavy ion irradiation, unfaulting and prismatic slipping mechanism cannot apply for interstitial Frank loops, and the behavior of these loops have dependence on their size and Schmid factor.