On the fragility of Cu47Ti33Zr11Ni8Si1 metallic glass

This study reports on calorimetric measurements of the glass transition at various heating rates stretching over three orders of magnitude for Cu47Ti33Zr11Ni8Si1 metallic glass powders synthesized by gas-atomization and subjected to varying thermal treatments. A Vogel-Fulcher-Tammann-type relation was fitted to the data recorded for the heating rate dependent shift of the glass transition. The fragility of the alloy is evaluated in terms of the fragility parameter. Its value is 44 for the as-prepared Cu47Ti33Zr11Ni8Si1 metallic glass powder and decreases with increasing annealing treatment temperature. The decrease in the fragility parameter is due to partial crystallization, which shifts the composition of the remaining supercooled liquid to that of a strong glass-forming alloy.