Technical Report Paper abstract bibtex
The undercooling of liquids is a common occurrence in solidification. The level of undercooling influences both the microstructural development by controlling phase selection during nucleation and the morphological evolution during the growth phase of solidification. The development of large liquid undercooling is linked to the kinetic control of solidification processes, including the suppression of heterogeneous nucleation during slow cooling and constrained growth during rapid quenching. The deepest undercoolings have been measured in droplet samples and approach 0.3-0.4 T m. At high undercooling, solidification can yield metastable product structures. These structures develop under a competitive phase selection kinetics controlled by heterogeneous nucleation. With heterogeneous nucleation, the analysis requires a clear identification and description of the multiplicity of sites and the hierarchy of potency in order to treat the active sites. Throughout the analysis of the kinetic processes involved in solidification well-defined experiments and physically realistic models are essential in revealing the controlling mechanisms and in modeling the overall microstructural development.