The interaction mechanism of screw dislocations with coherent twin boundaries in different face-centred cubic metals

The interaction between screw dislocations and coherent twin boundaries has been studied by means of molecular dynamics simulations for Al, Cu and Ni. Depending on the material and the applied strain, a screw dislocation approaching the coherent twin boundary from one side may either propagate into the adjacent twin grain by cutting through the boundary or it may dissociate within the boundary plane. Which one of these two interaction modes applies seems to depend on the material dependent energy barrier for the nucleation of Shockley partial dislocations.