Flux-induced structural modification and phase transformations in a Pd40Ni40Si4P16 bulk-glassy alloy

In order to uncover the mechanism of fluxing-enhanced undercooling, a study of the liquid structure in a Pd40Ni40Si4P16 bulk-glassy alloy was performed, which revealed that a flux-treated sample presents a shortened mean interatomic distance and an increased coordination number within the first shell, which results in a more densely packed local structure than in an unfluxed sample. In addition to the usual influence of fluxing to effect a deactivation of nucleation catalysts to yield enhanced undercooling, structural studies have discovered a new effect of fluxing. The local structural change induced by fluxing is associated with an increase in the delay time for the onset of nucleation. The prolonged transient period is also reflected by sluggish atomic transport in the fluxed sample, which promotes kinetic stability of the undercooled liquid.