Recent developments in the investigation of point defect structures in B2-type intermetallics were reviewed. Systematic X-ray and neutron diffraction experiments showed that B2 alloys exhibited a hybrid defect behavior. That is, 4 types of defect (antisite defects and vacancies) generally coexisted in this type of material. The results of careful density measurements strongly suggested that constitutional vacancies did not exist; even in NiAl. A thermodynamic model which was based upon the Bragg-Williams method reproduced well the observed trends in B2 NiAl and FeAl alloys.

Point Defects in B2-Type Intermetallic Compounds. M.Kogachi, T.Haraguchi: Materials Science and Engineering A, 2001, 312[1-2], 189-95