Formation of macroscopic phase-separated dual-layer melt-spun ribbon from Co–Si–B–Cu alloy

Formation of macroscopically phase separated Cu-colored melt-spun ribbon in (Fe0.5Cu0.5)100−B (x= 0, 5, 10, and 20) alloys

“…7(f)). Such a unique structure has never been reported in rapidly solidified ribbons of alloys, which have undergone simultaneously liquid phase separation and amorphous phase formation [1][2][3][4][5][6][7][8][9][10][11][12][13]. On the Fe 40 Cu 40 B 20 alloy ribbon (Fig.…”

“…Furthermore, rapid solidification can be used to change the material's solidification mode (for example, from eutectic to dendrite solidification mode) and for the suppression of segregation, structural refinement, liquid phase separation, and so on. Recently, the formation of a unique solidification structure in a rapidly solidified melt-spun ribbon was reported for alloys that underwent simultaneous liquid phase separation and an amorphous phase formation [1][2][3][4][5][6][7][8][9][10][11][12][13]. The formation of nano-scale emulsion-type structures (nanoscale globule-dispersed structures), multi-scale globule-dispersed structures, marble-type structures (entangled duplex structures), macroscopically phase-separated dual-layer structures, etc.…”

Formation of Various Types of Globules in Co–Cu–Si–B Immiscible Alloy with Amorphous Phase

“…7) Bulk metallic glass composites of Co-Cu-based immiscible alloys have been reported to form in Cu-Cu-Zr-Al alloy systems, such as (Cu 46 Among these alloy systems, the solidification structure of the Co-Cu-Si-B alloy systems significantly depends on the process and composition. The phase separation of Co-rich and Cu-rich liquids and the formation of an amorphous phase in a separated Co-rich liquid lead to the formation of specific solidification structures, such as macroscopically phaseseparated micrometer-order structures [i.e., dual-layer structure, 3,4) entangled-duplex structure, 5) and coreshell structure 6) ] and nanometer-ordered structure consisting of nanoemulsion-like structure in a macroscopically phase-separated Co-rich layer.…”

“…3,4) The Co-Si-B amorphous alloys are known to show excellent soft magnetic properties 10) and the Cu-based crystalline layer can act as the heat removal layer. To control the microstructure of the melt-spun (Co 0.75 Si 0.10 B 0.15 ) 70 Cu 30 alloy ribbons for their application as soft magnetic materials, the microstructure of the alloy needs to be systematically evaluated.…”

“…To control the microstructure of the melt-spun (Co 0.75 Si 0.10 B 0.15 ) 70 Cu 30 alloy ribbons for their application as soft magnetic materials, the microstructure of the alloy needs to be systematically evaluated. It is noteworthy that while the formations of the macroscopically phase separated structure 3,4) and the emulsion-like structure in the macroscopically phase separated Co-rich Co-Si-B base amorphous layers 5) have been evaluated, the microstructures of the macroscopically phase separated Cu-rich crystalline layers are yet to be investigated in detail. In this study, the microstructure of rapidly solidified melt-spun ribbons in immiscible Co CuSiB alloys was systematically evaluated focusing on globules embedded in a macroscopically phase-separated Cu-rich layer in melt-spun ribbons, and a new coreshell structure that differed from the observed coreshell structure formed in atomized powder in (Co 0.75 Si 0.10 B 0.15 ) 45 Cu 55 alloy 6) was first observed.…”