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1

The use of DSC curves and the Kronmüller theory to study the level of structural defects of Fe-based bulk amorphous alloys

Jeż Bartłomiej, Nabiałek Marcin

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 2

art. no. e144613

EN

This article presents the results of tests carried out on rapid quenched Fe-based alloys. The alloys were made using an injection-casting method. The actual structure of the alloys was also studied using an indirect method, based on H. Kronmüller's theorem. Based on analysis of the primary magnetization curves, in accordance with the aforementioned theory, it was found that Mo causes a change in internal regions associated with changes in the direction of the magnetization vector. The evolution of the thermal properties with increasing volume of Mo has been confirmed by the DSC curves. Addition of Mo, at the expense of the Nb component, results in changes to the crystallization process (i.e. the crystallization onset temperature and number of stages). The study showed that the addition of Mo at the expense of Nb reduces glass forming ability. Based on the DSC analysis, free volumes were determined for the alloys tested. These values were compared with the analysis of primary magnetization curves. It was found that the DSC curves can be used to indirectly describe the structure of amorphous alloys similar to the theory of the approach to ferromagnetic saturation. This approach is new and can be used by many researchers in this field.

2

Crystallization of Fe-Based Bulk Amorphous Alloys

Błoch K., Dośpiał M., Garus S.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 1

7--10

EN

The aim of this paper is to present the results of crystallization studies for the bulk amorphous (Fe0.61Co0.10Zr0.025Hf0.025 Ti0.02W0.02B0.20)98Y2, Fe61Co10TixY6B20, Fe61Co10Ti2Y7B20 alloys. The crystallization of the alloys was studied by differential scanning calorimetry (DSC). The amorphicity of the investigated alloys in the as-quenched state was testified using Mossbauer spectroscopy, X-ray diffractometry and transmission electron microscopy. Moreover, X-ray diffractometry was applied to structure investigations of partially crystallized samples. The crystallization process in the investigated alloys occurs in one or two stages. Two peaks in the DSC curves can be overlapped or well separated indicating the complex crystallization processes. From X-ray diffraction we have stated that in both types of devitrification the crystalline phase can be ascribed to the α-FeCo. In the first stage the crystalline grains seem to grow from the nuclei frozen in the samples during the rapid quenching, whereas in the second one both the growth of the existed grains and creation of new ones during annealing may occur.

PL

W pracy przedstawiono wyniki badań krystalizacji masywnych stopów amorficznych (Fe0.61Co0.10Zr0.025Hf0.025 Ti0.02W0.02B0.20)98Y2, Fe61Co10TixY6B20, Fe61Co10Ti2Y7B20 w postaci prętów. Krystalizację tych stopów badano wykorzystując skaningowy kalorymetr różnicowy (DSC). Amorficzność próbek w stanie po zestaleniu została zbadana przy użyciu spektroskopii Mössbauera, dyfrakcji promieni Röntgena oraz transmisyjnej mikroskopii elektronowej. Ponadto, dyfrakcję promieni X użyto do badań próbek częściowo skrystalizowanych. Na podstawie badań z wykorzystaniem DSC stwierdzono, że krystalizacja może przebiegać w jednym lub w dwóch etapach. Piki na krzywych DSC odpowiadające tym dwóm etapom mogą być położone blisko siebie lub wyraźnie rozdzielone. Pierwsze maksimum odpowiada tworzeniu się ziaren α-FeCo z zarodków powstałych podczas produkcji stopu, drugie natomiast związane jest z procesem tworzenia się ziaren fazy krystalicznej α-FeCo z zarodków powstałych podczas wygrzewania i rozrostem wcześniej powstałych ziaren.

3

Improvement of mechanical properties of Fe-based alloys by application of rapid solidification method and Ti doping

Gondro J., Błoch K., Nabiałek M., Dośpiał M., Szota M., Bukowska A., Pietrusiewicz P.

Inżynieria Materiałowa

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2014

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Vol. 35, nr 2

127--131

EN

The results of research into the microstructure and mechanical properties of Fe73T5Y3B19, Fe61Co10Y8Ti1B20 alloys are presented in this paper. Samples were obtained at the solidification speed of 104÷106 K/s in the form of ribbons of about 30 µm in thickness. All studies were conducted for samples in the as-cast state. Amorphous structure of the investigated alloys was confirmed by the X-ray diffractometry. The chemical composition determined from EDS studies was similar to the nominal composition of the alloy. Photos of the Vickers imprints, and the abrasion areas were obtained using an optical microscope for the matte side of the tape. The obtained results showed that the alloy with higher titanium content had much higher abrasion resistance as well as greater surface development.

PL

W pracy przedstawiono wyniki badań mikrostruktury oraz wybranych właściwości mechanicznych stopów Fe73T5Y3B19, Fe61Co10Y8Ti1B20 otrzymanych przy prędkości krzepnięcia 104÷106 K/s w postaci cienkich taśm o grubości około 30 µm. Badania przeprowadzono dla próbek stopów w stanie po zestaleniu. Amorficzność stopów potwierdzono badaniami rentgenowskimi. Skład chemiczny próbek został wyznaczony na podstawie badań z wykorzystaniem spektrometru rentgenowskiego EDS i jest zbliżony do nominalnego składu stopu. Zdjęcia próbek, odcisków Vickersa oraz obszarów wytarć wykonano z wykorzystaniem mikroskopu świetlnego. W pracy przedstawiono wyniki badań dla matowej strony taśmy. Wyniki badań zamieszczone w tej pracy pokazują, że stop z większą zawartością tytanu cechuje się znacznie większą odpornością na ścieranie, jak również większym rozwinięciem powierzchni.

4

Effect of Cooling Rate on Magnetic Properties, Size and Type of Structural Defects in the Volume of Bulk Amorphous Fe36 Co36 B19 Si5 Nn4 Alloy in the Form of Rods of Various Diameters

Nabiałek M., Dobrzańska-Danikiewicz A., Lesz S., Pietrusiewicz P., Szota M., Dośpiał M.

Archives of Metallurgy and Materials

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2014

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Vol. 59, iss. 1

263--268

EN

This paper presents the results of microstructure and magnetic properties analysis for bulk amorphous samples of Fe36 Co36 B19 Si5 Nn4 alloy in the form of rods of 1 mm, 2 mm, and 3 mm diameters in the as-cast state, produced using the method of injecting liquid alloy into cooled copper mold. The main purpose of the research was to examine the effect of solidification speed of the liquid material into amorphous state on the shape of initial magnetization curve as well as to determine the type and size of structural defects occurring in the volume of the material. In order to achieve these objectives, the magnetization measurements were carried out, which according to H. Kronmüller’s theory on magnetization behavior near the area called reaching the ferromagnetic saturation, allow to determine the type, size, and surface density of structural defects occurring in the volume of the sample. The analysis of reduced magnetization curves indicates that solidification speed of the liquid alloy into the amorphous state is the main determining factor for the shape of initial magnetization curve and for the type and size of structural defects formed in the sample, which affects such magnetic parameters as: coercive field (HC) or saturation magnetization (MS).

PL

W pracy przedstawiono wyniki badań mikrostruktury oraz właściwości magnetycznych masywnego stopu amorficznego Fe36 Co36 B19 Si5 Nn4 w stanie po zestaleniu. Próbki stopu zostały wytworzone w postaci prętów o średnicy 1 mm, 2 mm i 3 mm przy zastosowaniu metody wtłaczania ciekłego materiału do miedzianej formy chłodzonej wodą. Mikrostrukturę próbek w stanie po zestaleniu badano wykorzystując dyfrakcję promieni Rontgena. natomiast magnetyzację w silnych polach magnetycznych mierzono wykorzystując magnetometr wibracyjny (VSM). Głównym celem pracy było zbadanie wpływu czasu zestalania ciekłego materiału do stałego stanu amorficznego na przebieg pierwotnej krzywej magnesowania oraz określenie rodzaju i wielkości defektów strukturalnych występujących w badanych próbkach.

5

Arc-plasma spraying and suction-casting methods in magnetic materials manufacturing

Wysłocki J. J., Pawlik P.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 43, nr 1

463--468

EN

Purpose: The paper discusses two new technologies for producing magnetic materials which have been successfully developed in recent years at the Institute of Physics of the Czestochowa University of Technology and discusses properties of the materials obtained with the use of these methods. Design/methodology/approach: In this research the arc-plasma deposition of Nd2Fe14B powders onto a substrate either cooled with water or heated up to a temperature in the range from 773 to1023 K was applied. In the second method the suction of an arc-melted alloy to a water-cooled copper mould (the suction-casting method) was introduced. Moreover, microstructure, magnetic properties and domain structure of the produced samples were determined. Findings: It has been found that thin Nd2Fe14B strips obtained by the plasma method possess magnetic properties. It has also been demonstrated that the suction-casting method makes it possible to obtain both amorphous magnetically soft materials (e.g. Fe-Co-W-Zr-B), as well as magnetically hard nanocomposites (e.g. (Fe-Co)-(Pr-Dy)-B-Zr). Research limitations/implications: The main problem in the suction-casting method is to reduce the critical cooling rate required for the production of amorphous alloys and to increase the geometrical dimensions of amorphous specimens. Practical implications: Thin-layered Nd-Fe-B magnets produced by means of arc-plasma deposition can be applied directly onto the surface of electromagnetic equipment parts. Magnets with isotropic magnetic properties were obtained by applying layers onto the water-cooled copper substrate. Whereas, anisotropic magnets were obtained as a result of the arc-plasma deposition of powders onto the copper substrate heated up to 873 K. The most advantageous properties were achieved for the microcrystalline structure of a grain size close to the single-domain particle size (approx. 0.3 μm). Moreover, it has been demonstrated that the suction-casting method makes it possible to obtain bulk amorphous alloys of considerable sizes, such as rods of magnetically soft Fe-Co-W-Zr-B alloys of a diameter up to 2 mm, as well as Fe-Co-Pr-Zr-B tubes of a diameter up to 3 mm. It is also possible to produce magnetically hard nanocomposite materials of the (Fe-Co)-(Pr,Dy)-B-Zr type by annealing of metallic glasses. Originality/value: Successfully introduced new methods of magnetic materials manufacturing.

6

Nowe technologie wytwarzania materiałów magnetycznych

Wysłocki J. J., Pawlik P.

Hutnik, Wiadomości Hutnicze

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2006

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Vol. 73, nr 6

280-284

PL

Przedstawiono dwie nowe technologie wytwarzania materiałów magnetycznych: łukowo-plazmowe nanoszenie proszków oraz zasysanie roztopionego łukowo stopu do chłodzonej wodą formy (suction-casting). Zbadano magnetyczne i strukturalne właściwości cienkich warstw Nd-Fe-B nanoszonych plazmowo na podłoże miedziane o różnej temperaturze. Ponadto pokazano, że metoda suction-casting pozwala na uzyskiwanie zarówno amorfcznych materiałów magnetycznie miękkich (np. Fe-Co-W-Zr-B), jak i nano-kompozytów magnetycznie twardych, np. (Fe-Co)-(Pr-Dy)-B-Zr.

EN

New two technologies of the magnetic materials manufacturing are presented: arc-plasma spraying and suction casting. Thin Nd-Fe-B flms prepared by arc-plasma spraying at different substrate temperatures were investigated for their magnetic and structural properties. Moreover, it is shown that the suction-casting method is suitable for manufacturing of magnetically soft amorphous materials (e.g. Fe-Co-W-Zr-B) as well as hard nanocomposites, e.g. (Fe-Co)-(Pr-Dy)-B-Zr.