Nanocrystalline soft magnetic ribbons with high relative strain at fracture

Heil, T. M.; Wahl, Kathryn J.; Lewis, A. C.; Mattison, J. D.; Willard, M. A.

doi:10.1063/1.2742598

Cited by 19 publications

(2 citation statements)

References 18 publications

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“…10 Consequently, new graded processes, focused to obtain high-performance nanocrystalline magnetic materials with superior mechanical properties combined with excellent magnetic and/or electronic properties, are going on. [6][7][8] These graded mechanisms should be based on the fact that amorphous solids are thermodynamically metastable and amorphous to-crystalline phase transformation will be stimulated if sufficient energy to drive this process is supplied.…”

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Low temperature magnetic behaviour of glass-covered magnetic microwires with gradient nanocrystalline microstructure

Serrano

Hernando

Marı́n

2014

Journal of Applied Physics

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Slow nanocrystallization driving dynamics can be affected by the combination of two factors: sample residual stresses and sample geometry. This effect is evidenced at the initial stages of nanocrystallization of amorphous CoFeSiBCuNb magnetic microwires. Transmission electron microscopy observations indicate how crystallization at temperatures between 730 and 780 K results in a graded microstructure where the crystallization at the surface skin of the microwire, which remains almost amorphous, differs from that of the middle, where elongated grains are observed, and inner regions. However, samples annealed at higher temperatures present a homogeneous microstructure. The effect of gradient microstructure on magnetic properties has been also analyzed and a loss of bistable magnetic behaviour at low temperatures, from that obtained in the amorphous and fully nanocrystallized sample, has been observed and ascribed to changes in sign of magnetostriction for measuring temperatures below 100 K. V C 2014 AIP Publishing LLC.[http://dx.doi.org/10.1063/1.4862540] High performance materials are those essential to important modern applications as ultra-sensitive sensors, actuators and transducers, space power generators, high density magnetic storage media, electromagnetic waves shielding, etc., that should work in extreme environments. However, the full advantage that these materials can provide is strongly dependent on composition and microstructure.1 On the other hand, the concept of gradient materials that refer to the introduction of engineered chemical composition and/or microstructure parameter profiles has been used to tailor materials with desired properties and has gained much attention due to their potential applications. [2][3][4][5] In the case of magnetic materials, high-performance means operating at high frequency, high power densities, and high temperatures in extreme environments.6-8 These applications require soft magnetic materials not only preserving excellent conductivity, high permeability and saturation magnetization, low coercivity, low eddy-current losses, and high Curie temperatures 6-9 but also the necessary mechanical strength (i.e., toughness) for processing.Nanocrystallization from the amorphous state has become a promising method currently available for producing desirable amorphous-nanocrystalline structures with high magnetic characteristics but, generally, these processes involve mechanical properties deterioration associated to embrittlement and ultimate rupture strength decrease. 10Consequently, new graded processes, focused to obtain high-performance nanocrystalline magnetic materials with superior mechanical properties combined with excellent magnetic and/or electronic properties, are going on. [6][7][8] These graded mechanisms should be based on the fact that amorphous solids are thermodynamically metastable and amorphous to-crystalline phase transformation will be stimulated if sufficient energy to drive this process is supplied. Thermal annealing is a common method to ahead these tra...

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confidence: 99%

Low temperature magnetic behaviour of glass-covered magnetic microwires with gradient nanocrystalline microstructure

Serrano

Hernando

Marı́n

2014

Journal of Applied Physics

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“…In the past years, studies have mainly focused on the stress effects, soft magnetic properties, and the loss of the ribbon material. [8][9][10][11][12] Harjes et al presented the withstanding voltages of the coatings of Fe-based amorphous ribbon, 13,14 but the withstanding voltages were obtained under the condition of direct current (DC) or alternating current (AC), and the focus was not on the plasma physical mechanisms and characteristics during the breakdown courses. Optical methods were employed to explore the surface flashover mechanism of the solid-state insulators in large dimensions, [15][16][17] but the breakdown discharge and plasma channel expansion effects under the repetitive mode were not included.…”

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confidence: 99%