Simulation of small-angle tilt grain boundaries and their response to stress

The atomic structure and energy of small-angle tilt grain boundaries in bcc tungsten and fcc aluminum are determined by atomistic simulations. The results show the dependence of the arrangement of grain boundary dislocations and the grain boundary energy on the tilt axis, the misorientation angle between the two grains and the orientation of the grain boundary plane for investigated small-angle grain boundaries. Comparison is made with a dislocation model for grain boundaries. The response of the small-angle grain boundaries to external loading is simulated. It is found that the boundary may either migrate easily or not at all at the same applied loading, depending on the characteristics and the arrangement of the grain boundary dislocations.