Novel method for construction of high performance nanocrystalline FeCuNbSiB toroidal core

• Published in: Journal of alloys and compounds 2019-10, Vol.804, p.494-502
• Main Author: Günes, Taylan
• Format: Article
• Language: English
• Subjects: Amorphous alloys; Annealing; Coercivity; Deformation effects; Grain structure; Heat treatment; Hysteresis loops; Magnetic properties; Magnetostriction; Modulus of elasticity; Nanocrystalline alloy; Nanocrystals; Nanoindentation; Optical properties; Photomicrographs; Poisson's ratio; Saturation; Strain; Stress annealing; Stress induced winding system; Structural deformation; Tensile stress; Toroids; Ultrafines; Winding
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2019.07.031

In the current study magnetic, magneto-optical and microstructural properties of the amorphous Fe83Cu1Nb3Si5B8 alloy were properly investigated depending on the external treatments such as annealing and stress annealing. Kinetic nanocrystallization temperatures of certain ribbon were determined at the range of 500–510 °C. The amorphous ribbons produced in the as-spun state were subjected to tensile stress loading with and without rapid heat treatment of 510 °C during 5 s. Behaviors of certain ribbons were extensively investigated in terms of several factors such as magnetic properties, microstructural evaluation, magneto-optical effects and structural deformation by means of quasi-static hysteresis loops, XRD analyses, TEM micrographs, magneto-optical Kerr imaging and nanoindentation test. Present nanocrystalline Fe83Cu1Nb3Si5B8 alloy have allowed yielding not only ultrafine grain structure of around 7.02 nm but also saturation induction of 1.85 T, coercivity of 5.8 A.m−1 and saturation magnetostriction of 6 ppm. Additionally, based upon determined optimum stress annealing circumstances, toroidal nanocrystalline core was produced using a proposed stress induced winding (SIW) system. SIW system based principally on the gradient of the rotational speed of each mandrel in the standard toroidal core winding machine. Structural deformation of the core was determined by an analysis method performed on the ribbon. Accordingly, induced elastic modulus (E), Poisson's ratio (V) and residual strain (ε) in the ribbon under the influence of stress annealing by 200 MPa at 510 °C were found as 7.9 GPa, 0.39 and 0.031, respectively. •NC ribbon showed great magnetic capability after stress annealing was implemented (200 MPa + 510 °C).•The alloy system consisted of α-Fe grains with the size of 7.02 nm.•Air gaps between the stacked ribbons could be reduced around 84% after the tensile stress of 200 MPa.•SIW system offers a feasible way to produce high performance NC toroidal cores.•Elastic modulus, Poisson's ratio and residual strain were found as 7.9 GPa, 0.39 and 0.031.