In situ crystallization of Zr_(55)Cu_(30)Al_(10)Ni_5 bulk glass forming from the glassy and undercooled liquid states using synchrotron radiation

摘要

Real-time detection of crystal nucleation and growth in amorphous Zr_(55)Cu_(30)Al_(10)Ni_5 was performed for the first time. The experiments were performed at the European Synchrotron Radiation Facilities (ESRF) using monochromatic beam with energy of 90 keV corresponding to a X-ray wavelength of 0.137 A. Full X-ray spectra in transmission were obtained every 3 s. Crystallization was monitored both during heating of the amorphous alloy and during cooling of the liquid alloy to detect differences in the nucleating crystaline phases. We found that crystallization of the amorphous phase occurs via initial nucleation and growth of a metastable phase that transforms to equilibrium tetragonal Zr_2Cu before melting. However, no trace of nucleation of the metastable phase was obtained during cooling of the liquid alloy from above T_m and Zr_2Cu formed directly from the liquid.