Modification of dislocation emission sources at symmetric tilt grain boundaries in Ag by Cu solute atoms

A very small amount of immiscible solutes can dramatically decrease the ability of dislocations to nucleate from grain boundaries. In this paper we report the results of the molecular dynamics simulations which show that at larger concentrations, the solute effect becomes rather non-trivial: there are concentration ranges where even small addition of solutes considerably suppresses the dislocation nucleation from grain boundaries and there are concentration ranges where addition of new solutes almost does not change the dislocation nucleation ability. We reveal the atomic mechanism of these effects.