Constitution and magnetic properties of iron-rich iron-aluminum alloys

Taylor, A.; Jones, Randolph M.

doi:10.1016/0022-3697(58)90213-0

Cited by 399 publications

(62 citation statements)

References 13 publications

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“…The alloy as-filed reveals a smooth P(H) curve suggesting a random atomic distribution, and the internal field for 4nn Fe, which is conspicuous in the slowly cooled alloy, is now inconspicuous in the P(H) curve. The atomic ordering with DO3 type has been destroyed by cold working almost to the disordered state, as was first reported by Taylor and Jones (2). As the annealing at 673K proceeds, the appearance of Mossbauer spectra and P(H) curves is interesting.…”

Section: Mossbauer Spectra and Distribution Of Internal Fieldssupporting

confidence: 58%

Mössbauer Study on Atomic Reordering of Cold-Worked Iron-Aluminum Alloys

et al. 1981

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The process of atomic reordering of cold-worked Fe-Al alloys in the composition range from about 25 to 35 at%Al has been investigated by means of Mossbauer spectroscopy. Mossbauer spectra for the specimens filed and subsequently annealed were taken at each stage of annealing and analyzed to obtain the distribution of internal magnetic field in the alloys. Furthermore, for the alloy with 24.9 at%Al information on the neighbor configurations of constituent atoms was successfully able to be obtained directly from the Mossbauer spectra by assuming the Gaussian distribution function of internal magnetic field acting on iron atoms with various numbers of iron neighbors, and a detailed process of reordering during annealing was clarified.The ordered alloy with the DO3 type, which is either weakly magnetic or nonmagnetic depending on the composition, became strongly magnetic by cold working. The alloy as-filed was much complicated in structure, and the atomic configuration seemed to be distinctly different from that of the thermally disordered state. The alloy reordered very slowly in the course of annealing by way of the perfect disorder and the B2 type of order. The ordered alloy with the B2 symmetry, which is nonmagnetic, was partially disordered by cold working and changed into a weakly magnetic state. The alloy reordered promptly to its initial state by a relatively low temperature annealing.

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Section: Mossbauer Spectra and Distribution Of Internal Fieldssupporting

confidence: 58%

Mössbauer Study on Atomic Reordering of Cold-Worked Iron-Aluminum Alloys

et al. 1981

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“…To perform the calculations we used the following structures: ordered B2 or CsCl, B32 and D03 (see fig. 1), because they are the structures that appear in the Fe rich side of the phase diagram [2,11]. In order to define them we took into account the description made by F. S. Schmidt and K. Binder (12) which is shown in figure 1.…”

Section: Theoretical Calculationsmentioning

confidence: 99%

Propiedades electrónicas y magnéticas de las aleaciones Fe-Al

Apiñaniz¹,

Plazaola²

2000

Bol. Soc. Esp. Ceram. Vidr.

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This work presents ab-initio self-consistent calculations performed with the TB-LMTO code to study the different phases of the Fe-Al phase diagram, corresponding to the ordered structures B2, DO3 and B32 and for Fe 50 Al 50 and Fe 3 Al compositions. Both, unpolarized and spin-polarized calculations have been performed to deduce the energetic difference between the paramagnetic and ferromagnetic state of the corresponding structure. Calculations for the disordered structures have also been performed for the previously mentioned compositions. These results show that by disordering the alloy magnetism is enhanced and that the equilibrium lattice parameter increases. Keywords: Fe-Al alloys, TB-LMTO code, magnetic transformations, order-disorder. Propiedades electrónicas y magnéticas de las aleaciones Fe-AlEn este trabajo se presentan cálculos autoconsistentes ab-initio realizados con el método TB-LMTO (Tight Binding Linear Muffin Tin Orbital) con el fin de estudiar las diferentes estructuras que se presentan en el diagrama de fases de las aleaciones Fe-Al. Se han estudiado las estructuras ordenadas B2, DO3 y B32 para las siguientes concentraciones: Fe50Al50 y Fe3Al. Asimismo, se han realizado cálculos teniendo y sin tener en cuenta la polarización de spin con el fin de poder deducir la diferencia energética entre los estados ferromágneticos y paramágneticos de la misma estructura. Por otra parte se han realizado estos mismos cálculos para estructuras desordenadas y las mismas concentraciones. Los resultados muestran que mediante el desorden aumenta el magnetismo de estas aleaciones y crece el parámetro de red. Palabras clave: Aleaciones Fe-Al, código TB-LMTO, transformaciones magnéticas, orden-desorden.room temperature), B32 long range order was observed by Becker and Schweike in neutron scattering experiments (4). Calculations of model alloys show that the B32 phase has a tendency to exist at even larger deviations from stoichiometry than the B2 phase.It has been shown that these alloys are of the ferromagnetic disordered type (BCC, A2) for Al concentrations up to 23 at % Al independent of heat treatment (5). In alloys with Al content ranging from 0 to 30 at % the iron atoms carry their normal magnetic moment of 2.2 µ B when they have at least five or more iron atoms as nearest neighbours (6). The 30 at % Al composition is critical for these systems were the average magnetic moment per Fe atom decreases rapidly from 2.0 to 0.7 µ B ; coupled with this there is a large fall in the lattice parameter associated with a fall in the atomic radii as the disorder to order transition occurs (20 to 30 at % Al).By disordering the alloy paramagnetic-ferromagnetic transitions can be induced and these transitions could be related to the changes in volume and not only to nearest neighbour effects as is commonly assumed. As an example we can mention that x-ray diffraction of ball milled alloy of composition Fe 60 Al 40 shows an increase of the lattice parameter with milling time (7). This lattice parameter increase has been assumed...

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“…[16] However, Fe-Al alloys showed a more complicated trend which is closely related to the changes in the magnetic valence with the Al content. [17] In particular, they found that the lattice parameter in Fe-Al alloys increases up to~22 at. pct Al, then it decreases up to~33 at.…”

Section: Resultsmentioning

confidence: 99%

“…pct Al. According to Taylor and Jones, [17] this complexity can be attributed to the electron transfer to the Fe sites as Al is substituted for Fe, thus decreasing both the radii of Fe and Al. Another reason for the observed trend in our alloys is the fact that a significant portion of the Al atoms does not enter the D0 3 structure but is segregated in the Cu clusters in a ratio 2:1 as suggested by the previous 3D atom probe analysis [18] making the effect of Si on the crystal lattice parameter dominant.…”

Section: Resultsmentioning

confidence: 99%

Crystal Structure and Magnetic Properties of (Fe,Si,Al)-Based Nanocomposite Magnets Designed for Cryogenic Applications

Daniil

Fonda

Willard

2015

Metallurgical and Materials Transactions E

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In this work, we performed a detailed study of the crystallization, crystal structure, and magnetic properties of Fe 87Àz Si zÀx Al x Nb 3 B 9 Cu 1 nanocrystalline alloys that were designed primarily for low-temperature applications. In addition, their interesting low-temperature [77 K to 300 K (À196°C to 27°C)] magnetic properties (H c and M s ) were also investigated. These alloys were produced by annealing their amorphous precursors at 823 K (550°C). Si and Al substitution do not seem to alter the crystallization procedure and crystal structure of the parent alloy but reduces the lattice parameter, the Curie temperature, and the saturation magnetization. On the other hand, it improves the room temperature coercivity at small amounts (H c = 0.35 A/m for x = 3.5, z = 19) and changes its temperature dependence. As a result, a remarkably low H c value at 77 K (À196°C) of 0.45 A/m was observed for x = 6 and z = 23.5.

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Constitution and magnetic properties of iron-rich iron-aluminum alloys

Cited by 399 publications

References 13 publications

Mössbauer Study on Atomic Reordering of Cold-Worked Iron-Aluminum Alloys

Mössbauer Study on Atomic Reordering of Cold-Worked Iron-Aluminum Alloys

Propiedades electrónicas y magnéticas de las aleaciones Fe-Al

Crystal Structure and Magnetic Properties of (Fe,Si,Al)-Based Nanocomposite Magnets Designed for Cryogenic Applications

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Constitution and magnetic properties of iron-rich iron-aluminum alloys

Cited by 399 publications

References 13 publications

M&ouml;ssbauer Study on Atomic Reordering of Cold-Worked Iron-Aluminum Alloys

M&ouml;ssbauer Study on Atomic Reordering of Cold-Worked Iron-Aluminum Alloys

Propiedades electrónicas y magnéticas de las aleaciones Fe-Al

Crystal Structure and Magnetic Properties of (Fe,Si,Al)-Based Nanocomposite Magnets Designed for Cryogenic Applications

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Mössbauer Study on Atomic Reordering of Cold-Worked Iron-Aluminum Alloys

Mössbauer Study on Atomic Reordering of Cold-Worked Iron-Aluminum Alloys