Composition and non-equilibrium crystallization in partially devitrified co-rich soft magnetic nanocomposite alloys

Ohodnicki, Paul R.; Qin, Yueling; Laughlin, David E.; McHenry, Michael E.; Kodzuka, M.; Ohkubo, T.; Hono, K.; Willard, M. A.

doi:10.1016/j.actamat.2008.08.051

Cited by 51 publications

(23 citation statements)

References 28 publications

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“…In amorphous precursors to nanocomposites magnets, it is often possible to suppress formation of stable phase and to, therefore, take advantage of properties of metastable phase, as has been shown recently for Co-Fe nanocomposites [7]. In Fe-Ni-based nanocomposites, a similar phenomenon is observed in Fe-rich alloys [8], [9] where nucleation of the -phase is suppressed in favor of a metastable -phase that has a Curie [10].…”

Section: Introductionmentioning

confidence: 62%

Near Room Temperature Magnetocaloric Response of an (FeNi)ZrB Alloy

2011

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Mechanical alloying of Fe NiZr B powders leads to the formation of a -FeNi phase. In order to obtain single -phase, a powdered sample was solution annealed in the -phase field and water quenched. The Curie temperature of this powder was slightly higher than room temperature. The refrigerant capacity calculated for this alloy, kg for 5 T, is comparable to other prominent room temperature magnetocaloric materials, making this alloy a good candidate for magnetic refrigeration near room temperature with additional benefits that is non-rare earth containing and less expensive than many alternatives.

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Section: Introductionmentioning

confidence: 62%

Near Room Temperature Magnetocaloric Response of an (FeNi)ZrB Alloy

2011

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“…Recent suppression of the nucleation of the c-phase has been observed in Co-Fe-based nanocomposites at compositions where the binary Fe-Co phase diagram predict that the a-andcphases coexist. [3][4][5][6][7][8] In Fe-Ni-based nanocomposites, similar observations in Fe-rich alloys 11 show nucleation of the c-phase is suppressed in favor of a metastable a-phase.…”

Section: Introductionmentioning

confidence: 60%

“…The first indication of crystallization appears in an increase in intensity and narrowing of the amorphous peak at 400 C. As the peak is centered at 45.0 , it is attributed to {110} bcc planes consistent with the prior results. 4,12 At 500 C, the {111} fcc peak emerges centered at 44. 1 .…”

Section: Resultsmentioning

confidence: 99%

“…This is consistent with observations in prior work for this alloy system. [3][4][5][6][7][8] At 600 C a broad peak at 47.0 suggests crystallites with hcp stacking rather than fcc. As temperature is further increased this peak disappears at the expense of continued growth of the corresponding fcc peaks up to 700 C. Peaks due to a secondary crystalline phase, typically (Co,Fe) 23 Zr 6 or (Co,Fe) 2 Zr, 3 do not appear in the high temperature XRD patterns obtained here.…”

Section: Resultsmentioning

confidence: 99%

“…2 Fe-based alloys have attracted the most attention, as optimized alloys exhibit relatively high magnetic flux densities and low losses. Co-based alloys, with small or zero magnetostriction, a relatively large response to magnetic field annealing [3][4][5][6][7][8] and excellent mechanical properties making them interesting for magnetic sensors and high frequency applications. 9,10 In transforming amorphous precursors to nanocomposite magnets, it is possible to suppress stable phase formation and exploit properties of metastable phases.…”

Section: Introductionmentioning

confidence: 99%

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In-situ investigation of phase formation in nanocrystalline (Co97.5Fe2.5)89Zr7B4 alloy by high temperature x-ray diffraction

Kernion

Ohodnicki

McHenry

2012

Journal of Applied Physics

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Crystallization and phase evolution in an (Co 97.5 Fe 2.5 ) 89 Zr 7 B 4 amorphous alloy was studied by high temperature x-ray diffraction (HTXRD) and transmission electron microscopy (TEM). Co-based nanocomposite alloys have zero magnetostriction and a strong response to magnetic field annealing making them interesting for sensor and high frequency power applications. Amorphous alloys, synthesized by single roll melt-spinning, develop a nanocomposite structure after primary crystallization. After annealing at 540 C for 1 h, TEM images and diffraction patterns confirm a grain size of 19 nm and the presence of at least two phases. HTXRD results show preferential body centered cubic (bcc) nucleation and formation of multiple phases at various stages of crystallization. Only the face centered cubic (fcc) phase remained at temperatures above 600 C. On heating, the lattice parameter of the fcc phase increases at a rate higher than expected from thermal expansion. This is partially explained by an increase in the Fe-concentration in fcc crystallites.

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