Non-equilibrium transformation in hypercooled Fe83B17 alloy

Employing the method of glass fluxing combined with thermal cycling, hypercooling (ΔThyp) up to 460 K was achieved in the bulk Fe83B17 alloy melt. Within the achieved undercooling range, it was found that only one eutectic reaction occurs during rapid solidification. For ΔThyp < 386 K, α-Fe + tetragonal Fe2B phases were detected. For ΔThyp ≥ 386 K, a metastable phase Fe3B was found directly separating from the undercooled melt and remaining at room temperature. In terms of kinetic and structural analysis, phase selection between the metastable phase, Fe3B, and the stable phase, Fe2B, was interpreted. By isothermal annealing of the as-solidified samples subjected to ΔThyp ≥ 386 K, the metastable–stable transformation correlated with solid-state transformation is investigated.