Atomic structure of Pd81Si19 glassy alloy under high pressure

In situ high-pressure X-ray diffraction experiments and reverse Monte Carlo simulations on Pd81Si19 glassy alloy were performed up to similar to 35 GPa. High-quality structure factor data with a q range up to 13.5 angstrom(-1) were obtained. The pressure dependence of the relative volume of Pd81Si19 glassy alloy can be well described by a third-order Birch Murnaghan equation of state with bulk modulus of B-0 = 229 GPa and a pressure derivative of B-0(') = 2.7. The continuous and monotonic change of relative volume as a function of pressure does not indicate any first-order phase transitions in Pd81Si19 glassy alloy in the studied pressure range. The pressure dependence of the atomic structures was systematically investigated by means of bond angle distribution, the Honeycutt and Andersen index, Voronoi tessellation, total and partial coordination numbers, and local chemical ordering analyses. It is found that the topological and chemical atomic structures of the Pd81Si19 glassy alloy do not change much with pressure, indicating the stability of this material under pressure. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.