Nucleation kinetics of continuously cooling Fe–17 at.%B droplets produced by controlled capillary jet breakup

Abstract

A new method for the investigation of the nucleation kinetics of traveling droplets was applied to mono-size droplets of an Fe–17 at.%B alloy generated by a controlled capillary jet breakup process. The developed method determines the in-flight nucleation kinetics of droplets from metallographic data and simulated droplet-cooling schedules. An iterative procedure is used to cross-validate the metallographic data and the model predictions. With the cross-validated data and simulation models, nucleation temperatures of Fe–17 at.%B droplets were calculated for various diameters and cooling conditions and shown in the form of continuous-cooling transformation (CCT) diagrams. The critical cooling rate for the amorphous solidification of Fe–17 at.%B droplets was predicted as a function of droplet diameter and verified metallographically.