Cluster variation method for determining the energy of slip-induced anti-phase boundary in BCC alloys

The cluster variation method formalism in the irregular tetrahedron approxi mation has been applied to the determination of the anti-phase boundary (AP B) energies of anti-phases generated by the slip of multiple dislocations o n a single plane in BCC alloys. The formalism has been applied to BCC Fe-Al alloys and compared with experimental results in the same system. The resu lts shows that in the short-range:ordered (SRO) state; most of the resistan ce to dislocation motion is felt by the first moving dislocation, which cha racterises slip-plane softening. For the long-range ordered (LRO) state the calculation justifies the formation of superdislocation configuration as e xperimentally observed in the phases at room temperature deformation. The r esults have been discussed in connection with the experimentally observed d eformation modes of BCC Fe-Al alloys. (C) 2001 Elsevier Science Ltd. All ri ghts reserved.