Glass transition, crystallization kinetics and pressure effect on crystallization of ZrNbCuNiBe bulk metallic glass.

The glass transition behavior and crystallization kinetics of Zr[sub 48]Nb[sub 8]Cu[sub 14]Ni[sub 12]Be[sub 18] bulk metallic glass have been investigated by differential scanning calorimetry and x-ray powder diffraction (XRD). The activation energies of both glass transition and crystallization events have been obtained using the Kissinger method. Results indicate that this glass crystallizes by a three-stage reaction: (1) phase separation and primary crystallization of glass, (2) formation of intermetallic compounds, and (3) decomposition of intermetallic compounds and crystallization of residual amorphous phase. The pressure effect on crystallization is studied by in situ high-pressure and high-temperature XRD using synchrotron radiation. Two crystallization temperatures, observed by in-situ XRD, behave differently with varying pressure. The onset crystallization temperature increases with pressure with a slope of 9.5 K/GPa in the range of 0 to 4.4 GPa, while the another crystallization temperature keeps almost unchanged in the applied pressure range. The results are attributed to the competing processes between the thermodynamic potential barrier and the diffusion activation energy under pressure. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]