Heterogeneous nucleation in Zr-Cu-Al-Ag metallic glasses triggered by quenched-in metastable crystals - A time-resolved neutron diffraction study

Crystallization of Zr-Cu-Al-Ag bulk metallic glasses containing quenched-in crystals was studied by time-resolved in-situ neutron diffraction during isothermal annealing in the supercooled liquid region. The quenched-in crystals grew slowly at the beginning, indicating good thermal stability of the Zr-Cu-Al-Ag metallic glass alloys. The neutron diffraction results demonstrated that crystallization in Zr-Cu-Al-Ag metallic glasses was triggered by quenched-in crystals, rather than traditional heterogeneous nucleation mechanisms such as atomic-level impurities, container wall or surface oxides.