The interactions of vacancy loops, and stacking-fault tetrahedra, with point defects were studied by using computer simulations, with a long-range pair-potential for Cu. It was found that there was a qualitative difference in the mechanism of growth of vacancy loops and stacking-fault tetrahedra. Whereas vacancy loops could grow without limitation, the growth of stacking-fault tetrahedra which contained more than 91 vacancies was rather difficult. The structure of small vacancy loops (less than 217 vacancies) could change during growth and the loop could transform, in turn, into a completely dissociated loop with 6 small truncated stacking-fault tetrahedra, a faulted Frank loop with a Burgers vector of 1/3<111> and several intermediate configurations of a partly dissociated loop. The problem of estimating the binding energy of a vacancy in a vacancy loop or stacking-fault tetrahedron, as a function of size, was considered and several approximations were tested. The thermal stability of small vacancy loops with various shapes was studied by using molecular dynamics methods, and a vacancy-loop to stacking-fault tetrahedron transformation was observed.

Vacancy Loops and Stacking-Fault Tetrahedra in Copper II. Growth, Shrinkage, Interactions with Point Defects and Thermal Stability. J.N.Osetsky, A.Serra, M.Victoria, S.I.Golubov, V.Priego: Philosophical Magazine A, 1999, 79[9], 2285-311