In-situ detection of the onset crystallisation of Zr55Cu30Al10Ni5 from the bulk glass and the liquid states using synchrotron radiation

we performed real time detection of crystal nucleation and growth in bulk amorphous Zr55Cu30Al10Ni5 for the first time. Crystallisation was monitored both during heating of the amorphous alloy and during cooling of the liquid alloy in order to detect possible differences in the nature of the nucleating crystalline phases forming during heating from the amorphous phase and cooling from the liquid state respectively. The experiments were performed on the LD 11 beam line of the European Synchrotron Radiation Facilities (ESRF) with high flux high energy monochromatic beam capabilities. The energy of the photons used was 90 keV corresponding to an x-ray wavelength of 0.0137 nm. Induction heating at rates of the order of 10 to 100 K/s were performed followed by conventional cooling of samples in quartz crucibles under high vacuum. Full x-ray spectra in transmission were obtained every 3 seconds. It was found that crystallisation of the amorphous phase occurs via initial nucleation and growth of a metastable phase that transforms to equilibrium tetragonal Zr2Cu before melting. However, no trace of nucleation of the metastable phase was obtained during cooling of the liquid alloy from above T-m and Zr2Cu formed directly from the liquid.