In situ crystallization of Zr55Cu30Al10Ni5 bulk glass forming from the glassy and undercooled liquid states using synchrotron radiation

Real-time detection of crystal nucleation and growth in amorphous Zr55Cu30A l10Ni5 was performed for the first time. The experiments were performed at the European Synchrotron Radiation Facilities (ESRF) using monochromatic be am with energy of 90 keV corresponding to a X-ray wavelength of 0.137 Angst rom. Full X-ray spectra in transmission were obtained every 3 s. Crystalliz ation was monitored both during heating of the amorphous alloy and during c ooling of the liquid alloy to detect differences in the nucleating crystall ine phases. We found that crystallization of the amorphous phase occurs via initial nucleation and growth of a metastable phase that transforms to equ ilibrium tetragonal Zr2Cu before melting. However, no trace of nucleation o f the metastable phase was obtained during cooling of the liquid alloy from above T-m and Zr2Cu formed directly from the liquid. (C) 1999 Elsevier Sci ence B.V. All rights reserved.