Influence of Pd on formation of amorphous and quasicrystal phases in rapidly quenched Zr₂Cu_(1−x)Pd_x

Abstract

The role of Pd in the transformation from an amorphous state to a metastable icosahedral quasicrystalline phase in Zr₂Cu_(1−x)Pd_x (x = 0 to 1) metallic glasses was investigated using high-energy synchrotron X-rays and differential scanning calorimetry. The total scattering functions show an increasing development of the high-Q side of the second diffuse scattering peak at 5.09 Å⁻¹ with increasing Pd content. The reduced radial distribution functions reveals that the bonding distance of the Zr–(Pd/Cu) pairs increases from 2.76 to 2.82 Å when x increases from 0.00 to 1.00, while the distance for the Zr–Zr pairs remains almost constant at 3.10 Å. Thermal analysis and X-ray diffraction together show that an amorphous-to-quasicrystal phase transition is not observed in the Zr₂Cu alloy, but partial or total substitution of Cu by Pd in Zr₂Cu_(1−x)Pd_x alloys does lead to quasicrystal formation.

Acknowledgements

This research has been sponsored by the Division of Materials Sciences and Engineering, Office of Basic Energy Sciences, U.S. Department of Energy under contract DE-AC05-00OR-22725 with UT-Battelle and contract W-7405-ENG-82 with Iowa State University. The Midwest Universities Collaborative Access Team (MUCAT) sector at the APS is supported by the US Department of Energy, Office of Science, Basic Energy Sciences, through the Ames Laboratory. Use of the Advanced Photon Source was supported by the US Department of Energy, Office of Science, Basic Energy Sciences, under Contract No. W-31-109-Eng-38.