Dynamic Mechanical Relaxation and Crystallization Kinetics of Zr60Al10Co20Ag10 Metallic Glass

Abstract:

The dynamic mechanical relaxation behavior of a Zr₆₀Al₁₀Co₂₀Ag₁₀ metallic glass was investigated by dynamic mechanical analysis, and its thermal stability and crystallization kinetics were further examined by thermal analysis. The results show that the loss modulus of this alloy exhibits a significant broadening α-relaxation peak, and the relatively low activation energy of α-relaxation (3.78±0.21 eV) is associated with the early onset of crystallization. The temperature and frequency dependence of the dynamic mechanical relaxation behavior were analyzed using the Kohlrausch-Williams-Watts (KWW) model, yielding a low Kohlrausch exponent (β_KWW) value that indicates a wide distribution of relaxation time and pronounced dynamic heterogeneity. Using Kissinger equation, the activation energy for the onset of crystallization E_x, the first crystallization peak activation energy E_p1, and the second crystallization peak activation energy E_p2 of this metallic glass are calculated to be 424, 420, and 271 kJ/mol, respectively, suggesting good thermal stability. Crystallization kinetics results show that the first crystallization peak corresponds to a diffusion-controlled process, with an Avrami index =1.97±0.33, which is consistent with the diffusion-dominated growth theory.