A review was presented of atomic vacancies in intermetallic compounds. The intermetallic compounds included crystalline, quasicrystalline, and bulk metallic glass structures. Vacancies could be specifically characterized by their positron lifetimes, by coincident measurement of the Doppler broadening of the two quanta emitted by positron–electron annihilation, or by time-differential dilatometry. By these techniques, high concentrations and low mobilities of thermal vacancies were found in open-structured B2 intermetallics such as FeAl or NiAl, whereas the concentrations of vacancies were low and their mobilities high in close-packed structure as, e.g., L12-Ni3Al. The activation volumes of vacancy formation and migration were determined by high-pressure experiments. The favourable sub-lattice for vacancy formation was found to be the majority sub-lattice in Fe61Al39 and in MoSi2. In the icosahedral quasicrystal Al70Pd21Mn9 the thermal vacancy concentration was low, whereas in the bulk metallic glass Zr57Cu15.4Ni12.6Nb3Al10 thermal vacancies were found in high concentrations with low mobilities. This may determine the basic mechanisms of the glass transition. Making use of the experimentally determined vacancy data, the main features of atomic diffusion studies in crystalline intermetallics, in quasicrystals, and in bulk metallic glasses could be understood.

Vacancies and Atomic Processes in Intermetallics – From Crystals to Quasicrystals and Bulk Metallic Glasses. H.E.Schaefer, F.Baier, M.A.Müller, K.J.Reichle, K.Reimann, A.A.Rempel, K.Sato, F.Ye, X.Zhang, W.Sprengel: Physica Status Solidi B, 2011, 248[10], 2290–9