Study on crystallization kinetics of binary alloys through model colloidal mixtures

Since the discovery of amorphous alloys, extensive attentions have been paid to understand the mechanism of glass-forming. The structural studies on its underlying mechanism have met challenge on direct structural characterization. It has been shown that the phase behavior of colloids dispersed in a solvent is thermodynamically equivalent to that of atoms and small molecules, however, colloids can be studied with optical microscopy due to their relatively large size. In this work, we use a binary colloidal model system with the particle size ratio comparable to atomic ratio of reported binary bulk metallic glasses to study the topological effect on crystallization and glass-forming ability of binary metallic alloys (Cu–Hf and Cu–Zr systems). The crystallization kinetics and structure of the colloid system were studied by real-time optical examination and light scattering technique. The results exhibit that there are two confined regions in the mixing ratio (composition) range in the colloid system with an enhanced glass-forming ability and retarded crystallization kinetics. The agreement between results of the model system and the experimental data on the binary bulk metallic glass formation suggests that purely topological factor plays an important role in determining the glass-forming ability.