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A first-principles study of phase stability in NiAl and NiTi alloys

1992; Elsevier BV; Volume: 152; Issue: 1-2 Linguagem: Inglês

10.1016/0921-5093(92)90038-3

1873-4936

Marcel H. F. Sluiter, P. E. A. Turchi, F. J. Pinski, G. M. Stocks,

Rare-earth and actinide compounds

The thermodynamic stability of the b.c.c.- and f.c.c.-based ordered phases of NiTi and NiAl has been studied with a highly accurate first-principles electronic structure method. The occurrence of a martensitic transformation in NiAl B2 ordered intermetallic alloys will be discussed and related to the existence of intermediate structures between b.c.c.- and f.c.c.-based phases. It will be shown that closely related ordered structures can exist on f.c.c. and b.c.c. lattices in the composition range where the transformation occurs. A variety of antiphase boundaries in the B2 and L12 structures will be examined and the pertinent energies will be compared with experimental data. In addition, the rather unusual appearance of the NiTi B2 ordered structure in the phase diagram will be discussed.