Synergistic stabilization of metastable Fe_(23)B_6 and γ-Fe in undercooled Fe_(83)B_(17)

摘要

Previous investigations of undercooled liquid Fe_(83)B_(17) near the eutectic composition have found that metastable crystalline phases, such as Fe_(23)B_6, can be formed and persist down to ambient temperature even for rather modest cooling rates. Using time-resolved high-energy x-ray diffraction on electrostatically levitated samples of Fe_(83)B_(17), we demonstrate that the Fe_(23)B_6 metastable phase and fcc γ-Fe grow coherently from the undercooled Fe_(83)B_(17) liquid and effectively suppress the formation of the equilibrium Fe_2B + bec α-Fe phases. The stabilization of γ-Fe offers another opportunity for experimental investigations of magnetism in metastable fcc iron.