title: Magnetic field driving gradient effects on the microstructure in amorphous-nanocrystalline cobalt alloy ribbons.
abstract: Field effects on the early crystallization of Co-rich amorphous ribbons (Co(68.15)Fe(4.35)Si(12.5)B(15), atomic%) performed at 450 °C for 30 minutes in an applied 10 Oe longitudinal or transverse external magnetic field are investigated by comparing with the as-spun and annealed samples in zero applied magnetic field. Results indicate that the crystallization on the surface skin of the ribbon differs from that of the middle section due to the combined effects from the field direction and the defects or stress characteristics across the ribbons. In particular, the ribbons annealed under a transverse field exhibit an extremely distinct graded microstructure across the ribbon, which features amorphous-phased skin layers (top and bottom) of about 4-5 μm thickness and a middle amorphous-nanocrystalline composite layer about 10-12 μm thick, with the nanograins of 434 ± 99 nm dispersing in the amorphous matrix.
authors.affiliation: Key Laboratory of Aerospace Materials and Performance (Education of Ministry), School of Materials Science and Engineering, Beihang University, Beijing, 100191, China.
authors.forename: Zhaowei
authors.initials: Z
authors.lastname: Tang
authors.forename: Yujun
authors.initials: Y
authors.lastname: Song
authors.forename: Qiangqiang
authors.initials: Q
authors.lastname: Sun
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.forename: Yanwei
authors.initials: Y
authors.lastname: Jiang
mesh_terms: D003035:Cobalt / Q000737:chemistry* / Q000528:radiation effects*; D003460:Crystallization / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry / Q000528:radiation effects; D060526:Magnetic Fields; D008422:Materials Testing; D008968:Molecular Conformation / Q000528:radiation effects; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure*; D010316:Particle Size; D013499:Surface Properties / Q000528:radiation effects
chemical_list: D046911:Macromolecular Substances; D003035:Cobalt