X-ray absorption and diffraction spectroscopy of icosahedral Al-Cu-Fe quasicrystals under high pressure

Abstract We report in-situ extended X-ray absorption fine structure (EXAFS) and X-ray diffraction studies of quasicrystals under high pressure quasihydrostatic conditions. The EXAFS and diffraction experiments are combined for the first time to give a joint evolution of the short-range and long-range atomic order with pressure. EXAFS experiments performed at the Fe and Cu K absorption edges have been carried out for an icosahedral Al62Cu25.5Fe12.5 alloy from ambient pressure up to about 8 GPa (Fe edge) or 35 GPa (Cu edge). The local order around Fe and Cu atoms has thus been obtained as a function of pressure. X-ray diffraction patterns have been obtained for the same quasicrystal up to 35 GPa and these have given a variation in the 6D lattice parameter with pressure. A remarkable result is that the quasicrystal remains icosahedral up to the highest pressure. The evolution of the 6D lattice parameter and of the first-neighbour distances has provided values of the zero-pressure bulk modulus and of its firs...