Grain Boundary Sliding along Special Asymmetric Grain Boundaries in the Al Bicrystals: Atomistic Molecular Dynamics Simulation

To elucidate the mechanisms controlling the processes of sliding along grain boundaries (GBs), the energy characteristics of grain boundary shears for asymmetric GBs with tilts sigma 5{010}/{340}< 001 > and sigma 5{110}/{710}< 001 > in an Al bicrystal have been calculated by the molecular dynamics simulation method. The energy of generalized grain-boundary stacking faults (GB-SF) is determined, and the preferred directions and the energy barrier for grain-boundary sliding are established. The following characteristic feature of asymmetric boundaries is found: the number of different nonequivalent sections for GB sliding parallel to the plane of the GB for these kinds of boundaries is substantially higher than for symmetric ones. It is shown that the type of the section confining the GB has a substantial effect on both the geometry of the gamma surface and the energy characteristics of the grain-boundary SF (GB-SF).