It was recalled that an experimental study had revealed a large density of stacking-fault tetrahedra, but very low dislocation densities, in foils following deformation. This had been interpreted as being evidence for a new dislocation-free deformation mechanism which resulted in a very high rate of vacancy production. This proposition was investigated here by using large-scale computer simulations of bulk and thin films of Cu. In order to favour a dislocation-free deformation mechanism, dislocation nucleation was made very difficult by failing to introduce any potential dislocation sources into the initial configuration. The nucleation of dislocation loops was nevertheless observed, and the deformation was carried by the dislocations. The latter were nucleated as single Shockley partials. The large stresses which were required to nucleate dislocations resulted in a very high dislocation density, and therefore led to many inelastic interactions between the dislocations. These interactions created vacancies, and a very high vacancy concentration was quickly established.

Dislocation Nucleation and Vacancy Formation during High-Speed Deformation of FCC Metals. J.Schiøtz, T.Leffers, B.N.Singh: Philosophical Magazine Letters, 2001, 81[5], 301-9