Retained free energy as a driving force for phase transformation during rapid solidification of stainless steel alloys in microgravity

Schematic comparison of nucleation of a stable phase within a pre-existing metastable solid. a The primary phase has few defects or internal strain and significant mass transfer must occur to allow secondary nucleation, b the primary phase has many high-energy defects with associated internal strains—both conditions are relieved by secondary nucleation and the system energy decrease drives the transformation. In practice, this manifests itself as a reduction in the transformation dela