A study of grain boundary translational states in a Σ3[110]/(111) bicrystal

High-resolution electron microscopy images of a Σ3[110]/(111) bicrystal produced by heavy cold rolling and annealing show a multiplicity of grain boundary core structures. Two grain boundary states are separated by a partial grain boundary dislocation with Burgers vector b = 1 2 b₁ (where b₁ = 1 6[112] is the Burgers vector of a secondary dislocation). This implies a change in translational state. All other structures are related through continuous transport of atoms from one grain to the other resulting in [111] grain boundary steps. Calculations of the energy associated with the observed structures indicate that the two perfect twin states t = 0 and 2b₁ are stable, while all other grain boundary translational states are metastable.