Log-normal diameter distribution of Pd-based metallic glass droplet and wire

We have studied the formation of Pd(42.5)Cu(30)Ni(7.5)P(20) metallic glass droplets and wires in the gas atomization process. We demonstrate that the sizes of droplets and wires can be distinguished by the Ohnesorge number (O(h)), which is the proportion of the spinnability to the capillary instability, and the diameter distributions follow a log-normal distribution function, implying cascade fragmentation. For droplets, the number significantly increases at O(h) < 1 but the diameter gradually decreases. For wires, the number greatly increases at O(h) > 1 while the diameter steadies below 400 nm. Further, the wire diameter is quadrupled at O(h) = 16 due to the high viscosity which suppresses both capillary breakup and ligament elongation.