Structure of a glassy Zr₇₀Pd₃₀ alloy analysed by anomalous X-ray scattering coupled with reverse Monte Carlo simulation (AXS-RMC)

Abstract

The anomalous X-ray scattering (AXS) technique was applied to the structural analysis of a rapidly quenched Zr₇₀Pd₃₀ glassy alloy. The AXS analysis and subsequent reverse Monte Carlo (RMC) simulation allowed three partial pair distribution functions to be obtained, together with a three-dimensional structural model. A Voronoi polyhedral analysis of the nearest neighbour region confirms the overall preference of an icosahedral-like local structural unit. An ideal icosahedron around Pd, composed of Pd–Zr pairs with covalent nature, is suggested to be one of the important structural features for the easy formation of the nano-icosahedral phase by low temperature annealing.

Keywords:

• zirconium–palladium alloy
• glassy alloy
• anomalous X-ray scattering
• reverse Monte Carlo simulation

Acknowledgements

The authors wish to express their gratitude to Professor M. Nomura, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, Japan, for his help on the AXS measurements (Proposal No. 2009G091). A part of this work was supported by the Ministry of Education, Science, Sports and Culture, Grant-in-Aid for Scientific Research (B), 20340147.