Grain-boundary dissociation by the emission of stacking faults

A range of [110] symmetric tilt grain boundaries (GB's) are investigated in several fee metals with simulations and high-resolution electron microscopy. Boundaries with tilt angles between 50.5 degrees and 109.5 degrees dissociate into two boundaries 0.6 to 1.1 nm apart. The dissociation takes place by the emission of sticking faults from one boundary that are terminated by Shockley partials at a second boundary. This is a general mode of GB relaxation for low stacking fault energy metals. The reasons for the occurrence of this relaxation mode are discussed using the theory of GB dislocations.