Atomic scale modelling was used to study the structure and energy of {110} twist grain boundaries with various coincidence-site-lattice misorientations in α-iron. The small angle {110} twist grain boundaries contains a hexagonal dislocation network of two sets of ½〈111〉 and one set of 〈001〉 dislocation segments. The 〈001〉 segments were almost pure screw dislocations and the angle between the two 1/2〈111〉 segments varies from 83 to 109° for the rotation angle from 0.25 to 5.40°. This twist grain boundary dislocation structure agrees well with an experimental observation that was not explained adequately so far. The large-angle twist grain boundaries consisted of periodic patterns rather than a dislocation network. The variation of the boundary energy with the rotation angle could be well fitted to the Read-Shockley equation in the low-angle range. An apparent cusp in the curve of the boundary energy against the rotation angle was found and discussed.

Atomic Scale Modeling of {110} Twist Grain Boundaries in α-Iron - Structure and Energy Properties. J.B.Yang, Y.Nagai, M.Hasegawa, Y.N.Osetsky: Philosophical Magazine, 2010, 90[7-8], 991-1000