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

Abstract:

Based on the classical nucleation theory, a time-temperature-transformation (TTT) curve of Zr₆₁Ti₂Cu₂₅Al₁₂ alloy was constructed, and its critical cooling rate R_c 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.