Nature of the Beta-Phase of Nickel-Aluminum System
FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OH
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During the detailed study of system nickel - aluminum in the field of Beta-phase with X-ray method 1 it was established that at room temperature the Beta-phase preserves uniformity from 45.25 to 60 at. Ni. Later than 2 during the determination of the boundary o Beta-phase from the nickel side were obtained the same results. Data with respect to a change in lattice constant and density of alloys with composition change allowed Bradley and Taylor to establish that the solid solutions in the region of the uniformity of Beta-phase have uncommon structure. Alloys with 50 at. Ni have the body-centered cubic structure of the type CsCl with a regulated atomic arrangement. With an increase in the content of nickel are formed solid solutions by the statistical substitution of aluminum atoms in crystal lattice by nickel atoms. The substitution however, of nickel atoms by aluminum atoms is observed only to 51 at. Al with further increase in the content of aluminum solid solutions have defective structure, since part of the positions in the lattice, occupied earlier by nickel, remains free. This leads to the change of the number of atoms in the unit cell, which on the boundary of phase reaches value of 1.84.
- Inorganic Chemistry
- Properties of Metals and Alloys