Nanoquasicrystalline phase formation in binary Zr-Pd and Zr-Pt alloys

This paper reports nanoquasicrystalline phase formation in Zr100-xPdx (x = 30 and 35) and Zr80Pt20 binary alloys and the kinetics of the nanoquasicrystallization process. While the icosahedral phase (i-phase) forms as a metastable phase in the transient stage during the crystallization of Zr-Pd amorphous alloy, it forms directly from the liquid during melt-spinning of Zr-Pt alloy, The isothermal kinetics studies show that i-phase forms from the Zr70Pd30 amorphous alloy by the primary crystallization process with the Avrami exponent in the range of 1.5-2.5. Three-dimensional atom probe analysis results suggest that the i-phase is slightly enriched with Zr with respect to the matrix and its composition is close to Zr75Pd25. The tendency of quasicrystallization of Zr-based alloys appears to have correlation with the enthalpy of mixing of the system. (C) 2001 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.