Influence of Pd on formation of amorphous and quasicrystal phases in rapidly quenched Zr2Cu(1-x)Pdx

摘要

The role of Pd in the transformation from an amorphous state to a metastable icosahedral quasicrystalline phase in Zr2Cu(1-x)Pdx(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 5.09A(-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 2.82A when x increases from 0.00 to 1.00, while the distance for the Zr-Zr pairs remains almost constant at 3.10A. 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)Pdx alloys does lead to quasicrystal formation.