Dissociation of Tilt Dislocation Walls in Au

The movement or dissociation of dislocations is signifi cantly important for better understanding the plastic deformation mechanisms and mechanical properties of metals. It is commonly believed that a dislocation < 110 >/2 in Au is easy to dissociate into a pair of Shockley partial dislocations < 112 >/6 due to low stacking fault energy(SFE). Contrary to this prevailing perception, the present atomistic modeling demonstrates that this reaction could be completely suppressed when dislocations < 110 >/2 are grouped into tilt walls, consistent with our experimental observations. Such phenomenon is actually the extreme case accompanying with the variation of Burgers vectors of partials with tilt angle, as revealed by a series of simulations, from which it is clearly seen that the Burgers vectors of partials deviate considerably from that of Shockley partials, enormously depending on the tilt angle. Our fi ndings could facilitate a better understanding on many phenomena and properties of face-centered cubic metals(FCC).