Development of Fe–P–C–Cu Immiscible Amorphous Alloys with Liquid Phase Separation

Abstract

The rapid solidification microstructure and magnetic properties of melt-spun ribbons in the (Fe_0.75P_0.125C_0.125)_100-xCu_x (at%) alloys were investigated, focusing on the occurrence of liquid-phase separation and simultaneous amorphous-phase formation. The (Fe_0.75P_0.125C_0.125)_100-xCu_x alloys were designed as a combination of Fe–P–C alloy with high glass-forming ability and Cu. Amorphous-phase formation was observed in the melt-spun ribbons of the (Fe_0.75P_0.125C_0.125)_100-xCu_x (x = 10, 20) alloys. For the melt-spun ribbons of the (Fe_0.75P_0.125C_0.125)_100-xCu_x (x = 10) alloy, a composite of Fe–P–C amorphous matrix and FCC–Cu globules was obtained, whereas in the melt-spun ribbons of the (Fe_0.75P_0.125C_0.125)_100-xCu_x (x = 20) alloy, multistep liquid-phase separation resulted in a particular solidification microstructure.

STEM-HAADF image and elemental mapping of Fe, P, and Cu of the rapidly solidified melt-spun ribbons of the (Fe_0.75P_0.125C_0.125)_100-xCu_x (x = 20) alloy: (a) low magnification image, (b1) elemental mapping focusing on region A, (b2) elemental mapping focusing on region B. (Online version in color.)