In situ high-pressure x-ray diffraction study of icosahedral Al-Cu-TM (TM = V, Cr, M) alloys

Icosahedral AI-Cu-TM (TM: transition metals = V, Cr, Mn) alloys were obtain ed by single-roller melt-spinning in a protective inert-gas atmosphere. The high-pressure properties up to 20 GPa were investigated by in situ energy- dispersive x-ray diffraction at a synchrotron source using a gas-membrane d iamond-anvil cell. No phase transitions could be observed. The bulk modulus of the Al-Cu-TM quasicrystalline phases was found to increase with the Hum e-Rothery factor. Moreover, the bulk modulus of the quasicrystalline phase is imposed by the bulk modulus of the transition metal element. The derived values for the first pressure derivative B'(0) indicate strong anharmonic contributions in the lattice potentials.