Metastable phase formation in eutectic solidification of highly undercooled Fe₈₃B₁₇ alloy melt

Adopting molten glass denucleating combined with thermal cycling, high undercooling up to 460 K was achieved in the bulk Fe₈₃B₁₇ alloy melts. Results from XRD, SAED and DTA show that, for undercoolings beyond the critical value 386 K, a metastable phase Fe₃B remains in the as-solidified structure at room temperature. The effect of undercooling on the observed phenomenon was interpreted in terms of a time-dependent nucleation theory, i.e., the competitive nucleation between the metastable phase, Fe ₃B and the stable phase, Fe₂B.