It was found that the lattice constant, after quenching from a given temperature, increased with increasing Al content up to stoichiometry. It then exhibited a decrease, or a gradual change. However, there was a tendency for the lattice constant to be larger than that reported previously for the same quenching temperatures. The maximum deviation was estimated to be about 100K. This implied that the retained vacancy concentration was lower in the present samples than in previous samples. The mobility of the thermal vacancies which were created was thought to depend upon the temperature and upon the particle size of the powdered samples which were used. This then led to a larger mobility for higher temperatures and finer particle sizes. The particle sizes in the present case were expected to result in easier annealing-out of vacancies at lower temperatures, such as 773K. Quenching from higher temperatures (1173K) led to difficulty in retaining the vacancies during quenching. It was clearly shown here that the vacancy concentration increased, on both sub-lattice sites, with increasing quenching temperature.

Random Vacancy Distribution in the B2-Type Intermetallic Compound FeAl M.Kogachi, T.Haraguchi: Scripta Materialia, 1998, 39[2], 159-65