CRYSTALLIZATION ON SUPERCOOLED LIQUID IN METALLIC ZR-CU-AL GLASSES

Crystallization behaviors are isothermally examined on supercooled-liquid and amorphous states in metallic Zr-Al-Cu glasses using differential scanning calorimetry. On the basis of a kinetic analysis, it is examined that the crystallization occurs with a zero nucleation rate below the glass transition temperature T(g) and a nearly steady-state nucleation rate above T(g). Arrhenius relation between effective time lag tau of nucleation and isothermal temperature appears as a curvature for alloys revealing a wide supercooled liquid region and a straight line for alloys without wider supercooled-liquid region. The differences are attributed to the effects of viscosity on nucleation at supercooled liquid. The difference in morphology during crystallization between amorphous and supercooled-liquid states was also confirmed.