The quasicrystallization at the initial stage under viscous flow at 673 K (20 K above the glass transition temperature) was investigated in a Zr 65Al7.5Ni10Cu12.5Pd5 bulk glassy alloy. The compressive deformation at strain rates of 2×10 -3s-1 and 1×10-2s-1 was subjected to the bulk glassy alloy for 60 s followed by the preannealing for 120 s for thermal equilibration in an Ar atmosphere. The glass undergoes Newtonian and non-Newtonian flow at the strain rates of 2×10-3s -1 and 1×10-2s-1, respectively. The linear viscous flow brings a significant decrease in the first exothermic peak in the differential scanning calorimetry (DSC) curve corresponding to the transformation from glassy to icosahedral phase, but is identical to that in the reference sample annealed for 180 s at 673 K without deformation. However, the number of icosahedral particles in the transmission electron microscopy image as well as the decrease of the first exothermic peak in the DSC curve in the nonlinear viscous flow is much less as compared with those in the linearly deformed and reference samples. These results indicate the suppression of the transformation from the glassy to icosahedral phase by the nonlinear viscous flow. The suppression of the transformation is suggested to be originated from the retardation of the growth by the stress-induced disordered atomic configuration in the glassy state during the nonlinear viscous flow.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)