Atomic scale simulation of the (310) [001] symmetric tilt grain boundary in the B2 stoichiometric FeAl ordered alloy

The T = 0 K atomic structure of the (310) [001] symmetric tilt grain boundary in the B2 ordered FeAl stoichiometric alloy was studied by means of numerical simulations using a semi-empirical potential. The approach based on the relaxation of geometric models is insufficient (because the variants cannot be discriminated) and intergranular composition changes cannot be properly accounted for in a simple independent-defect framework. Interactions between defects are thus essential to classify unambiguously the structures according to their stability. A pseudo-symmetric variant is found to be the most stable one at T = 0 K. It is very close to the pseudo-symmetric model of the coincidence site lattice theory and its central plane is made up of Fe atoms only. This is the indication of a possible tendency to Fe segregation in this B2 ordered FeAl alloy.