Dependence of diffusion on the alloy composition in ZrTiCuNiBe bulk glasses

Abstract

The diffusion coefficients of impurities in ZrTiCuNiBe-bulk glasses with different Be/Ti ratio were measured in the temperature range around the glass transition using the technique of secondary ion mass spectrometry. During long time annealing, the Zr 41Ti 14Cu 12.5Ni 10Be 22.5 glass (V1) undergoes an amorphous decomposition and the diffusion coefficients decrease by more than one order of magnitude. Two glasses, Zr 41Ti 8.7Cu 12.5Ni 10Be 27.8 (D1) and Zr 41Ti 16.5Cu 12.5Ni 10Be 20 (D2), which were produced to represent the decomposition phases of V1, also show a tendency of decomposition and time-dependent diffusion coefficients. Diffusion measurements performed at short annealing times yield only small differences between the temperature dependencies of the diffusion coefficients of the different impurities in all alloys. In general, the size rule is obeyed, i.e. the activation energies of diffusion increase with increasing atom size. The Arrhenius curves are not linear, indicating a significantly higher activation energy above about 580 K than below this temperature. No systematic effect of glass composition on the diffusion is observed.