Quasicrystals under pressure: a comparison between Ti-Zr-Ni and Al-Cu-Fe icosahedral phases

Single-phase icosahedral phases (i-phases) of TiZrNi and AlCuFe alloys were obtained by single roller melt-spinning in protective argon atmosphere. Th e high-pressure (up to 25 GPa) compression properties of i-TiZrNi and i-AlC uFe were investigated by in situ energy-dispersive synchrotron radiation (S R) diffraction experiments using a gas-membrane diamond-anvil cell. In cont rast to i-AlCuFe, reproducible deviations from the Birch-Murnaghan equation of state were noticed in the form of hysterezis loops during the first com pression cycles of i-TiZrNi alloys. This response of quasicrystalline matte r to hydrostatic pressure conditions is here reported for the first time. P lastic deformation processes and effects related to the small grain size of the rapidly-quenched TiZrNi alloys are tentatively considered as possible explanations. (C) 1999 Elsevier Science B.V. All rights reserved.