Thermophysical properties of Zr₆₅Cu_17.5Ni₁₀Al_7.5 bulk metallic glass

This study investigates the thermophysical properties of Zr₆₅Cu_17.5Ni₁₀Al_7.5 bulk metallic glass during its amorphous-to-crystalline transformation. Differential scanning calorimetry was used to examine the glass transition and crystallization temperatures, enthalpy of crystallization and activation energy. Dynamic mechanical analysis and laser flash analysis were used to determine the storage and loss moduli, thermal diffusivity and thermal conductivity, respectively. Heating-cooling cycles induced structural relaxation and irreversible changes in the amorphous material. Structural relaxation at increasing aging temperatures below glass transition temperature resulted in the increase in the storage modulus and higher loss factor in comparison with the as-cast state. Crystallization led to the formation of intermetallic phases and improved thermal conductivity. Overall, the fully crystalline material exhibited the highest thermal conductivity and diffusivity. Heat treatment at 390 °C for 20 min and at 400 °C for 5 min enhanced plasticity, attributed to shear bands, crystalline phases, and structural relaxation.