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1
Content available remote Enhanced magnetoelastic performance in Pr/Mn-doped Laves phase (Tb,Ho)Fe2 compounds
Wang M. K., Liu J. J., Lv X. J., Ding Q. L., Li F., Pan Z. B., Xia W. X., Du J.
Materials Science Poland
|
2020
|
Vol. 38, No. 4
707--714
EN
Magnetostrictive TbxHo0.8−xPr0.2Fe1.8Mn0.1 (0 ⩽ x ⩽ 0.20) alloys are prepared by arc-melting and subsequent annealing. The dopant of Pr/Mn introduced into RFe2 compounds effectively stabilizes the forming of single C15 Laves phase at ambient pressure. The easy magnetization direction (EMD) varies when Tb content increases, which is accompanied by a crystalstructural transition. EMD lies along ‹1 0 0› axis for x ⩽ 0.05, rotating to ‹1 1 1› axis for x ⩽ 0.12, with a tetragonal symmetry changing to a rhombohedral one. Magnetocrystalline-anisotropy compensation is obtained with the optimized composition of x = 0.12, shifting to the Tb-poor side in comparison to Pr/Mn-free counterpart. An enhanced effect on magnetoelastic properties is achieved in Tb0.12Ho0.68Pr0.2Fe1.8Mn0.1, which simultaneously possesses a low anisotropy and high magnetostriction performance, i.e. λs ~ 420 ppm, λ111 ~ 970 ppm, and a large low-field λa ~ 390 ppm/2 kOe, being 30 % higher than that of Pr/Mn-free compound. Combining low-cost light rare earth Pr with the lower Tb content, Tb0.12Ho0.68Pr0.2Fe1.8Mn0.1may make it promising solution in magnetostrictive applications.
2
Content available remote Dynamic magnetoelastic properties of TbxHo0.9−xNd0.1(Fe0.8Co0.2)1.93/epoxy composites
Shen W. C., Lin L. L., Shen C. Y., Xing S., Pan Z. B.
Materials Science Poland
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2019
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Vol. 37, No. 2
257--264
EN
TbxHo0.9−xNd0.1(Fe0.8Co0.2)1.93/epoxy (0 ⩽ x ⩽ 0.40) composites are fabricated in the presence of a magnetic field. The structural and dynamic magnetoelastic properties are investigated as a function of both magnetic bias field Hbias and frequency f at room temperature. The composites are formed as textured orientation structure of 1–3 type with 〈1 0 0〉 preferred orientation for x ⩽ 0.10 and 〈1 1 1〉-orientation for x ⩾ 0.25. The composites generally possess insignificant eddy-current losses for frequency up to 50 kHz, and their dynamic magnetoelastic properties depend greatly on Hbias. The elastic modulus (E3H and E3B) shows a maximum negative ΔΕ effect, along with a maximum d33, at a relatively low Hbias ~ 80 kA/m, contributed by the maximum motion of non-180° domain-wall. The 1–3 type composite for x ⩾ 0.25 shows an enhanced magnetoelastic effect in comparison with 0 to 3 type one, which can be principally ascribed to its easy magnetization direction (EMD) towards 〈1 1 1〉axis and the formation of 〈1 1 1〉-texture-oriented structure in the composite. These attractive dynamic magnetoelastic properties, e.g., the low magnetic anisotropy and d33,max as high as 2.0 nm/A at a low Hbias ~ 80 kA/m, along with the light rare-earth Nd element existing in insulating polymer matrix, would make it a promising magnetostrictive material system.
3
Analiza zmian mikrostuktury stali SANICRO 25 po długotwałym starzeniu
Sroka M., Zieliński A., Golański G.
Hutnik, Wiadomości Hutnicze
|
2018
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Vol. 85, nr 10
355--358
PL
W pracy przeprowadzono analizę zmian mikrostruktury i procesów wydzieleniowych faz wtórnych dla austenitycznej stali Sanicro 25 (22Cr25NiWCoCu). Badany materiał poddany był długotrwałemu starzeniu w czasie do 20 000 h w temperaturze 700 i 750°C. W początkowym okresie starzenia obserwowano wydzielanie licznych, bardzo drobnych węglików chromu typu M23C6 oraz fazy Lavesa. Po długotrwałym starzeniu w zależności od temperatury ujawniono występowanie faz wtórnych: M23C6, MX, NbCrN, fazy Lavesa oraz fazy σ. Uzyskane wyniki badań stanowią element charakterystyk materiałowych wykorzystywanych w ocenie trwałości eksploatacyjnej elementów części ciśnieniowej kotłów energetycznych.
EN
The paper presents the analysis of microstructure changes and secondary phase separation processes for austenitic Sanicro 25 steel (22Cr25Ni- WCoCu). The tested material was subjected to long-term aging for up to 20,000 hours at 700 and 750°C. In the initial period of aging, the formation of numerous, very fine M23C6 chromium carbides and the Laves phase was observed. After prolonged aging, depending on temperature, the occurrence of secondary phases M23C6, MX, NbCrN, Laves phase and phase was revealed. The obtained test results are an element of the material characteristics used in the assessment of the service life of elements of the pressure part of power boilers.
4
Content available Hyperfine interactions in Tb0.27-xYxDy0.73Fe2 compounds at 295 K
Krawczyk A., Zwoźniak A., Guzdek P., Stoch P., Zachariasz P., Suwalski J., Pszczoła J.
Nukleonika
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2013
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Vol. 58, No. 1
133-135
EN
This paper concerns the synthesis of yttrium-dilute Tb0.27-xYxDy0.73Fe2 intermetallic series with a borderline compound Tb0.27Dy0.73Fe2 known as Terfenol-D by arc melting, XRD analysis and 57Fe Mössbauer effect studies at 295 K. XRD analysis (295 K) shows that all samples crystallize in a cubic, Fd3m, MgCu2-type structure. The lattice parameter increases along with yttrium content. Mössbauer effect spectra for the Tb0.27-xYxDy0.73Fe2 series collected at 295 K consist of two subspectra due to easy direction of magnetization <111>. Hyperfine interaction parameters: isomer shift, magnetic hyperfine field and a quadrupole splitting were obtained from the fitting procedure of the spectra.
5
Content available Hydrogen ordering effects in Laves - phase YFe2
Ostrasz A.
Nukleonika
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2013
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Vol. 58, No. 1
77-81
EN
Mössbauer spectroscopy and X-ray diffraction measurements were performed before and after hydrogenation of YFe2 Laves phase in order to investigate the effect of hydrogen on their structural and magnetic properties. The experimental results show an instant change of both the lattice parameters and the hyperfine field. The results are interpreted due to the phase decomposition of the parent intermetallic in the aftermath of creation of stoichiometric hydrides YHc (c = 0.9; 2.5).
6
Content available Hyperfine interactions in Ho(Fe1-xCox)2 compounds at 295 K
Bednarski M., Stoch P., Bodnar W., Zachariasz P., Pszczoła J., Suwalski J.
Nukleonika
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2010
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Vol. 55, No. 3
279-284
EN
Synthesis of Ho(Fe1–xCox)2 intermetallic compounds, studies of their crystal structure and 57Fe Mössbauer effect analysis were carried out at 295 K. X-ray measurements evidence a pure cubic Fd3m, C15, MgCu2-type Laves phase. The unit cell parameter decreases non-linearly with composition parameter x. Mössbauer effect spectra for the Ho(Fe1–xCox)2 series were composed of a number of locally originated subspectra due to random Fe/Co nearest neighbourhoods. Hyperfine interaction parameters, i.e. isomer shift, the magnetic hyperfine field and a quadrupole interaction parameter were determined from the fitting procedure of the spectra, for both the individual nearest neighbourhoods, and for the sample as bulk. As a consequence of Fe/Co substitution a Slater-Pauling type curve for the average magnetic hyperfine field vs. x is observed. The correlation between the local magnetic hyperfine fields and the average magnetic hyperfine fields is related to weak and strong ferromagnetism of the transition metal sublattice.
7
Content available remote The influence of molybdenum on stress corrosion in Ultra Low Carbon Steels with copper addition
Bogucki R., Mazur М., Pytel S.
Archives of Foundry Engineering
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2010
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Vol. 10, iss. 3 spec.
219--224
EN
The influence of molybdenum content on the process of stress corrosion of ultra-low carbon structural steels with the addition of copper HSLA (High Strength Low Alloy) was analyzed. The study was conducted for steels after heat treatment consisting of quenching and following tempering at 600°C and it was obtained microstructure of the tempered martensite laths with copper precipitates and the phase Laves Fe2Mo type. It was found strong influence of Laves phase precipitate on the grain boundaries of retained austenite on rate and development of stress corrosion processes. The lowest corrosion resistance was obtained for W3 steel characterized by high contents of molybdenum (2.94% Mo) which should be connected with the intensity precipitate processes of Fe2Mo phase. For steels W1 and W2 which contents molybdenum equals 1.02% and 1.88%, respectively were obtained similar courses of corrosive cracking.
8
Content available remote Precipitation of Laves phase Fe2Mo type in HSLA steel with copper addition and high content of molybdenum
Bogucki R., Miernik K., Pytel S.
Archives of Foundry Engineering
|
2010
|
Vol. 10, iss. 3 spec.
213--218
EN
The results of mechanical properties and microstructure of low-carbon copper bearing steel after quenching and tempering at temperature range of processing precipitation of particles rich in copper and particles intermetallic phase are presented in this paper. When content molybdenum increases in tempering temperature range from 550°C to 600°C that decrease of the impact energy measured at room temperature was observed. Microstructure analysis was conducted by transmission electron microscope (TEM) and was disclosed the occurrence of Fe2Mo Laves phase on crystallites boundaries of retained austenite. Observed sudden drop of ductility in higher-molybdenum content steels (1,88 % and 2,94 %) should be connected with occurrence precipitation processes of the hard and brittle Laves phase in range of discussion tempering temperatures.
9
Content available Hyperfine interactions in Tb0.27Dy0.73(Fe1–xCox)2 compounds at 77 K
Bodnar W., Szklarska-Łukasik M., Stoch P., Zachariasz P., Pszczoła J., Suwalski J.
Nukleonika
|
2009
|
Vol. 54, No. 4
227-232
EN
The synthesis of materials, crystal structure and 57Fe Mössbauer effect studies at 77 K were performed for intermetallics Tb0.27Dy0.73(Fe1–xCox)2. The starting compound Tb0.27Dy0.73Fe2 of this Fe/Co substituted series is known as Terfenol-D. XRD measurements evidence a pure cubic Laves phase C15, MgCu2-type. The determined unit cell parameter decreases across the series. Co substitution introduces a local area, in the subnanoscale, with random Fe/Co neighbourhoods of the 57Fe atoms. Mössbauer effect spectra for the Tb0.27Dy0.73(Fe1–xCox)2 series collected at 77 K consist of a number of locally originated subspectra due to random composition of Fe and Co atoms in the nearest neighbourhood. Hyperfine interaction parameters: isomer shift, magnetic hyperfine field and a quadrupole interaction parameter were obtained from the fitting procedure of the spectra, both for the local area and for the sample as bulk. As a result of Fe/Co substitution, a Slater-Pauling type curve for the average magnetic hyperfine field vs. Co content in the Tb0.27Dy0.73(Fe1–xCox)2 series is observed. It is found that the magnetic hyperfine fields corresponding to the local area sorted out against Co contribution in the Fe/Co neighbourhoods also create a dependence similar to the Slater-Pauling type curve.
10
Content available remote Wodór w związkach międzymetalicznych typu faz Lavesa ziem rzadkich z manganem
Figiel H., Paja A.
Przemysł Chemiczny
|
2005
|
T. 84, nr 11
863-867
PL
Wśród związków międzymetalicznych ziem rzadkich i itru z metalami przejściowymi pochłaniających wodór szczególnie interesujące są związki typu faz Lavesa z manganem. W związkach tych pod wpływem wodoru zachodzą strukturalne i magnetyczne przemiany fazowe oraz zmiany ich właściwości. W pracy przedstawiono i omówiono obserwowane zjawiska dla wodorków REMn2Hx (RE = Y, Gd, Tb, Dy, Ho, Nd, Sm i Er) wskazując ich zależność od temperatury, rodzaju ziemi rzadkiej i koncentracji wodoru.
EN
A review with 34 refs. covering (Y, Gd, Tb, Dy, Ho, Nd, Sm, or Er)Mn2Hx hydrides, their prepn., Laves phases, structure and H-induced modifications, increase in vol. and magnetic properties in relation to H concn., crit. behavior, diffusion and ordering of H, and formation of the hydrides at pressures of up to 20 GPa.
11
Investigation of ZrFe2 and ZrCo2 Under Very High Pressure of Gaseous Hydrogen and Deuterium
Filipek S. M., Jacob I., Paul-Boncour V., Percheron-Guegan A., Marchuk I., Mogilyanski D., Pielaszek J.
Polish Journal of Chemistry
|
2001
|
Vol. 75, nr 12
1921-1926
EN
New hydrides and deuterides of Laves cubic phases ZrFe2 and ZrCo2 were synthesized by high hydrogen (deuterium) pressure technique. For both Laves phases the symmetry of lattice does not change but a large expansion of lattice parameter (by 8% for ZrFe2 and by 4.5% for ZrCo2) occurs during hydrides (deuterides) formation. In contrast to the rela-tively stable hydride (if stored in an inert atmosphere) formed in ZrFe2, the ZrCo2H2 de-composes easily at 25°C. Large lattice expansion of ZrFe2 during the deuteride formation changes only slightly its magnetic properties.
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