SHEAR FAULTS AND DISLOCATION CORE STRUCTURE SIMULATIONS IN B2 FEAL

Embedded atom potentials were derived for the Fe-Al system reproducing lattice and elastic properties of B2 FeAl. The structure and energy o f vacancies, antisites and anti phase boundaries (APBs) were studied. A significant decrease in the APE energy was obtained for Fe-rich B2 a lloys. Shear fault energies along the {110} and {112} planes were comp uted showing that stable planar faults deviated from the exact APE fau lt. Care structures and critical Peierls stress values were simulated for the [100] and [111] dislocations. The superpartials created in the dissociation reactions were not of the 1/2[111] type, but 1/8[334] in accordance with the stable planar fault in the {110} planes. The resu lts obtained for these simulations are discussed in terms of the mecha nical behavior of FeAl and in comparison with B2 NiAl. (C) 1997 Acta M etallurgica Inc.