Composition and precipitation behavior of icosahedral Al–Pd–Mn quasicrystals

Icosahedral Al–Pd–Mn phase was found to be stable in a compositional range [B. Grushko, et al., J. Alloys Comp. 290 (1999) 164]. Its stability range also depends on temperature. This is favorable for the formation of precipitates in the icosahedral phase by cooling. We demonstrate the precipitation in the “standard” single icosahedral quasicrystals produced by the Czochralski technique. Annealing of the quasicrystals at 800–840°C resulted in the dissolution of the precipitates and they reappeared after annealing at 700–500°C. The relation of this effect to the diffuse scattering in the icosahedral phase is discussed.