Metallic glass nucleation couples density fluctuations and structural preordering
Researchers tracked the early stages of crystallization across pure elements and alloys, establishing a unified nucleation mechanism.
Scientists have determined that density fluctuations and structural preordering emerge simultaneously during the earliest stages of crystallization in disordered metallic systems, according to a study published in the Proceedings of the National Academy of Sciences pnas.org
Proceedings of the National Academy of Sciencespnas.orgOpen source ↗. The analysis evaluated pure elements, intermetallic compounds, and glass-forming alloys to resolve long-standing questions regarding how atomic order initiates in supercooled liquids.
Previous models, largely generalized from hard-sphere colloidal systems, proposed that crystallization initiates primarily in structurally preordered regions, treating density changes as a secondary factor. The new findings demonstrate that both phenomena are coupled. This simultaneous emergence reflects local atomic rearrangements where free-volume reduction, denser packing, and bond-orientational order develop together.
The authors reported that this coupled behavior provides an empirical foundation for a unified nucleation framework across disordered materials.
