2019 Volume 60 Issue 4 Pages 554-560
The solidification microstructure and magnetic properties of rapidly solidified melt-spun ribbons in Cu43.2Ag32.0La4.8Fe20 (at%) alloy, which was designed as the combination of the Cu–Ag-based Cu54Ag40La6 alloy with high glass-forming ability and Fe, was investigated. The composite of an amorphous matrix and dispersed crystalline phases were obtained in the melt-spun ribbons. The spherical BCC-Fe nanocrystals, which were surrounded by Cu-rich crystalline phases, were embedded in a Cu–Ag–La-based amorphous matrix. The particular solidification structure in melt-spun ribbons can be explained by liquid-phase separation to form major Cu–Ag–La-rich and minor Fe-rich liquids, an amorphous phase formation in major Cu–Ag–La-rich liquid, and the crystallization of the separated Fe-rich liquid globules during the cooling of the thermal melt. The melt-spun ribbon shows typical ferromagnetic magnetic properties caused by the 10 nm-ordered spherical BCC-Fe nanocrystals.
This Paper was Originally Published in Japanese in J. Jpn. Soc. Powder Powder Metallurgy 65 (2017) 45–51. To explain more precisely the background, the purpose of the study, experimental procedures, and results, some parts of the contents were slightly revised. Reference 10) was added as the reference for the Fe–Ag-based liquid-phase-separation-type amorphous alloys. References 11–13) were added to explain the liquid-phase-separation behavior in the Fe–Cu-based alloy system in more detail. Reference 14) was added to explain the relationship between an amorphous-phase formation and the mixing enthalpy of constituent elements in more detail. Reference 27) was added to explain the cooling rate during the arc-melting process in more detail. References 31–33) were added as references for the Co–Cu-based liquid-phase-separation-type amorphous alloys.