Investigation on non- isothermal Crystallization Kinetics and Nanoindentaion Analysis of Melt Spun Processed Zr55Co30Ti15 Metallic Glass

This study investigates the thermodynamics, crystallization kinetics, and mechanical response of melt-spun Zr55Co30Ti15 metallic glass (MG) using Differential Scanning Calorimetry (DSC) and nanoindentation techniques. Crystallization behaviour was analysed at heating rates of 10, 20, 30, and 40 K/min. Kissinger's method revealed activation energies of 215.05 and 257.62 kJ/mol for the first and second crystallization peaks, confirming a higher activation energy barrier for atomic rearrangements and stability of the MG. The Avrami coefficient, ranging from 2.0 to 0.6 and 4.5 to 0.6 for the first and second peaks, respectively, indicates that the initial dense atomic packing hinders diffusion, with nucleation rates increasing as crystallization progresses. Nanoindentation studies reveal that annealing significantly affects hardness and elastic modulus. The as-cast sample is the softest, with hardness increasing and modulus varying with annealing temperatures due to structural relaxation and crystallization. At 375°C, the hardness increases while the modulus decreases; at 444°C, both hardness and modulus rise due to partial crystallization; and at 520°C, extensive crystallization results in maximum hardness (22.85±3.14 GPa) and modulus (205.57±2.68 GPa). Scanning probe microscopy and high-Resolution transmission electron microscopy show shear band evolution with increasing crystallization. These findings highlight the role of thermal processing in influencing crystallization kinetics and mechanical properties of Zr55Co30Ti15 MG, guiding its optimization for various applications