Early stage crystallization kinetics in metallic glass-forming alloys

• Heterogeneous nucleation may precede the homogeneous one in an alloy.
• High kinetic constants and the nucleation rate at the initial stage.
• Metallic glasses have heterogeneous nucleation sites which saturate later.

The crystallization kinetics and structural changes of a few metallic glassy alloys were monitored using X-ray diffraction, transmission electron microscopy, differential scanning and isothermal calorimetry methods. Microstructural observations were used to estimate the nucleation and growth rates. A clear comparison of the differences in the crystallization kinetics in the metallic glassy samples is observed at the early and later crystallization stages.