Kinetic Behavior of Supercooled Liquid of Zr₆₁Ti₂Cu₂₅Al₁₂ Amorphous Alloy: by Flash Differential Scanning Calorimetry

Based on the classical nucleation theory, a time-temperature-transformation (TTT) curve of Zr61Ti2Cu25Al12 alloy was constructed, and its critical cooling rate Rc was estimated and modified as about 63 K/s. The reliability of this estimation was evaluated using the glass-forming ability criteria, and the dominant roles of nucleation rate I and growth rate U on the crystallization mechanism in different supercooled liquid regions were explained. Combining flash differential scanning calorimetry with conventional thermal analysis, a heating rate range spanning six orders of magnitude (10-2–104 K/s) was achieved for the Zr61Ti2Cu25Al12 amorphous alloy, demonstrating the heating-rate dependence of kinetic behavior of supercooled liquid over an ultra-wide range. Results show that firstly, the dependence of heating rate on characteristic temperatures follows the Vogel-Fulcher-Tammann equation. Secondly, the small change in fragility coefficient (m=30–41) means that its supercooled liquid structure changes relatively smoothly with temperature, exhibiting “strong” liquid behavior to a certain extent, making the alloy have a certain glass-forming ability. This study provides technical guidance and theoretical basis for the preparation of Zr61Ti2Cu25Al12 amorphous alloy, especially for the plastic forming in the supercooled liquid region and the formulation of heat treatment process.