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. The high-pressure (up to 25 GPa) compression properties of i-TiZrNi and i-AlCuFe were investigated by in situ energy-dispersive synchrotron radiation (SR) diffraction experiments using a gas-membrane diamond-anvil cell. In contrast to i-AlCuFe, reproducible deviations from the Birch-Murnaghan equation of state were noticed in the form of hysterezis loops during the first compression cycles of i-TiZrNi alloys. This response of quasicrystalline matter to hydrostatic pressure conditions is here reported for the first time. Plastic 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.