Wyniki wyszukiwania - BazTech

1

Microstructure and mechanical properties of amorphous/crystalline ductile liquid immiscible Fe-Si-B-In alloy produced by two-component melt-spinning

Ziewiec K., Wojciechowska M., Mucha D., Ziewiec A.

Metallurgy and Foundry Engineering

|

2017

|

Vol. 43, no. 1

57--66

EN

The two-component melt-spun (TCMS) Fe71.25Si9.5B14.25In5 alloy was produced from Fe75Si10B15 and Fe67.5Si9B13.5In10 alloys. The microstructure of the TCMS alloy was investigated by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). A tensile test of the alloy resulted in a tensile strength of Rm = 1040 MPa, yield strength Re= 919 MPa, total plastic elongation ɛtot = 3.29%, and traces of plastic deformation on the surface of the Fe-Si-B-In TCMS sample. Microstructural analysis of the amorphous/crystalline composite and tensile sample free surface show the reason for the ductility of the sample in relation to the Fe75Si10B15 alloy.

PL

Stop Fe71,25Si9,5B14,25In5 wytworzono w wyniku odlewania z tygla dzielonego na wirujący walec miedziany dwóch stopów (metoda TCMS): Fe75Si10B15 i Fe67,5Si9B13,5In10. Mikrostrukturę stopu TCMS badano za pomocą skaningowego mikroskopu elektronowego oraz dyfraktometru rentgenowskiego. Z przeprowadzonej statycznej próby rozciągania uzyskano wytrzymałość na rozciąganie stopu Rm= 1040 MPa, granicę plastyczności Re= 919 MPa, wydłużenie całkowite εtot = 3,29 %. Na powierzchni próbki stopu Fe-Si-B-In TCMS po zerwaniu zaobserwowano także ślady odkształcenia plastycznego. Analiza mikrostruktury otrzymanego amorficzno-krystalicznego kompozytu oraz powierzchni swobodnej próbki wyjaśniają przyczynę ciągliwości próbki w stosunku do stopu Fe75Si10B15.

2

Wytwarzanie przyrostowe stopów amorficznych metodą selektywnego stapiania laserowego

Żrodowski Ł., Wysocki B., Błyskun P., Wróblewski R., Kurzydłowski K.J., Święszkowski W.

Mechanik

|

2017

|

R. 90, nr 1

50--51

PL

W artykule opisano proces optymalizacji stapiania proszków szkła metalicznego na bazie żelaza. Stapianie prowadzono przy różnych parametrach mocy lasera i strategiach przyrostowego wytwarzania – tak, aby uzyskać wysoką zawartość fazy amorficznej. Wyniki badań potwierdzają istotny wpływ mieszania jeziorka ciekłego metalu oraz szybkości nagrzewania wierzchniej warstwy materiału na amorfizację.

EN

In the paper optimization process for selective laser melting of Fe-based metallic glass powder has been described. Melting process has been conducted with various laser power and parameters to increase materials amorphisation degree. Results showed strong influence of melt pool mixing and heating rate on amorphisation.

3

Struktura i zdolność do zeszklenia stopów Fe-Co-Zr-Mo-W-B domieszkowanych Gd

Kotynia K., Pawlik P., Hasiak M.

Hutnik, Wiadomości Hutnicze

|

2017

|

Vol. 84, nr 9

425--427

PL

W artykule przedstawiono wyniki badań stopów amorficznych Fe58Co10Zr10Mo5W2B15Gdx (x = 0, 1, 2, 3, 4, 5) wytworzonych w postaci taśm o grubości nie przekraczającej 35 μm. Badania strukturalne przeprowadzono za pomocą dyfrakcji rentgenowskiej (XRD), natomiast badania kalorymetryczne przy użyciu skaningowej kalorymetrii różnicowej (DSC). Głównym celem pracy była optymalizacja parametrów procesu wytwarzania szkieł metalicznych oraz określenie wpływu składu chemicznego stopów na ich zdolność do zeszklenia.

EN

The paper presents the results of research on the Fe58Co10Zr10Mo5W2B- 15Gdx (x = 0, 1, 2, 3, 4, 5) amorphous alloys produced fabricated in the form of the ribbon of the thickness below 35 μm. The X-ray diffraction (XRD) and the differential scanning calorimetry (DSC) have been employed in the structural and the thermal analysis examination respectively. The main objective of the study was to optimize the parameters of the metallic glasses fabrication process and to determine the effect of the alloys chemical composition on their glass forming ability.

4

Structure and properties of Fe-Cr-Mo-C bulk metallic glasses obtained by die casting method

Pilarczyk W., Nowosielski R., Januszka A.

Journal of Achievements in Materials and Manufacturing Engineering

|

2010

|

Vol. 42, nr 1-2

80-87

EN

Purpose: The goal of this work is to investigate structure and properties of Fe54Cr16Mo12C18 alloy rods with different diameters obtained by the pressure die casting method. Design/methodology/approach: Master alloy ingot with compositions of Fe54Cr16Mo12C18 was prepared by induction melting of pure Fe, Cr, Mo, C elements in argon atmosphere. The investigated material were cast in form of rods with different diameters. Glassy and crystalline structures were examined by X-ray diffraction. The microscopic observation of the fracture morphology was carried out by the SEM with different magnification. The thermal properties of the studied alloy were examined by DTA and DSC method. Findings: These materials exhibit high glass-forming ability, excellent mechanical properties and corrosion resistance. Research limitations/implications: It is difficult to obtain a metallic glass of Fe54Cr16Mo12C18 alloy. The investigations carried out on the different samples of Fe54Cr16Mo12C18 bulk metallic alloy allowed to state that the studied ribbon was amorphous whereas rods were amorphous – crystalline. Originality/value: The formation and investigation of the casted Fe-Cr-Mo-C bulk materials and the study of glass-forming ability of this alloy.

5

Preparation, structure and properties of Fe-based bulk metallic glasses

Nowosielski R., Babilas R.

Journal of Achievements in Materials and Manufacturing Engineering

|

2010

|

Vol. 40, nr 2

123-130

EN

Purpose: The work presents preparation methods, structure characterization and chosen properties analysis of Fe-based bulk metallic glasses in as-cast state. Design/methodology/approach: The studies were performed on Fe43Co14Ni14B20Si5Nb4 metallic glass in form of rings, plates and rods. The amorphous structure of tested samples was examined by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) methods. The thermal properties of the glassy samples was measured using differential scanning calorimetry (DSC). The soft magnetic properties examination of tested material contained coercive force, initial magnetic permeability and magnetic permeability relaxation measurements. Findings: The XRD and TEM investigations revealed that the studied as-cast samples were amorphous. Broad diffraction halo is typical for metallic amorphous structures that have a large degree of short-range order. The characteristics of the fractured surfaces showed different zones, which might correspond with different amorphous structures of studied materials. The temperature interval of the supercooled liquid region (ÄTx) defined by the difference between Tg and Tx, is as large as 56 K for the rod with diameter of 3 mm. Differences in coercivity and magnetic permeability between samples with different thickness might be resulted by some difference of amorphous structure. Practical implications: The centrifugal casting method and the pressure die casting method are useful to produce bulk amorphous materials in form of rings, plats and rods. Originality/value: The preparation of studied Fe-based bulk metallic glass in form of rings, plates and rods is important for the future progress in research and practical application of that glassy materials.

6

Glass-forming ability analysis of selected Fe-based bulk amorphous alloys

Nowosielski R., Babilas R.

Journal of Achievements in Materials and Manufacturing Engineering

|

2010

|

Vol. 42, nr 1-2

66-72

EN

Purpose: The paper mainly aims to present the structure and thermal stability of selected Fe-based bulk metallic glasses: Fe72B20Si4Nb4 and Fe43Co14Ni14B20Si5Nb4. Design/methodology/approach: The investigated samples were cast in form of the rods by the pressure die casting method. The structure analysis of the studied materials in as-cast state was carried out using XRD and TEM methods. The thermal stability associated with glass transition temperature (Tg), onset (Tx) and peak (Tp) crystallization temperature was examined by differential scanning calorimetry (DSC). Several parameters have been used to determine the glass-forming ability of studied alloys. The parameters of GFA included reduced glass transition temperature (Trg), supercooled liquid region (deltaTx), the stability (S) and (Kgl) parameter. Findings: The XRD and TEM investigations revealed that the studied as-cast metallic glasses were fully amorphous. Changes of the onset and peak crystallization temperature and the glass transition temperature as a function of glassy samples thickness were stated. The good glass-forming ability (GFA) enabled casting of the Fe72B20Si4Nb4 and Fe43Co14Ni14B20Si5Nb4 glassy rods. Practical implications: The obtained examination results confirm the utility of applied investigation methods in the thermal stability analysis of examined bulk amorphous alloys. It is evident that parameters Trg, deltaTx, Kgl, S could be used to determine glass-forming ability of studied bulk metallic glasses. Originality/value: The success of fabrication of studied Fe-based bulk metallic glasses in form of rods with diameter up to 3 mm is important for the future progress in research of this group of materials.

7

Glass forming ability of binary Ni60+xNb40-x (x=0;1;2) alloys

Nowosielski R., Januszka A., Pilarczyk W.

Journal of Achievements in Materials and Manufacturing Engineering

|

2010

|

Vol. 42, nr 1-2

73-80

EN

Purpose: This paper presents the investigations results of fabrication and structure tests binary Ni-Nb metallic glasses. Design/methodology/approach: The studies were performed on Ni60+xNb40-x (x=0, 1, 2) alloys in form of ribbon and rods up to 2 mm. For the purpose of fabrication test pieces, melt spinning and pressure die casting methods were used. The main index for determine glass forming ability was thickness of specimens. To the tests of samples structure X-ray diffraction phase analysis (XRD) and scanning electron microscopy (SEM) were used. Owing to good mechanical properties of Ni-based metallic glasses, microhardness of cast rods were examined. Findings: X-ray diffraction and SEM analysis have revealed that samples in form of ribbons were amorphous, while cast rods were crystalline. Practical implications: The relationship between amorphous structure and good mechanical properties could be promising for many engineering application. The Ni-based bulk metallic glasses are newcomers engineering materials which may be applied to a new type pressure sensor exhibiting higher capability and higher sensitivity Originality/value: Paper present quite new type of binary metallic glasses based on Ni. For the sake of alloy simplicity it is possible that this alloys will be used in many applications.

8

The microstructure of rapidly quenched Fe-Cu-based alloy with a liquid miscibility gap

Kozieł T., Kędzierski Z., Zielińska-Lipiec A., Latuch J.

Inżynieria Materiałowa

|

2010

|

Vol. 31, nr 3

470-473

EN

The microstructures of rapidly quenched Fe37Cu25Si13B9Al8Ni6Y2 alloy are presented. Rapid cooling (melt spinning technique) of the melt enabled in situ formation of amorphous-crystalline composites. Four different melt ejection temperatures, in the range from 1330 to 1520°C, were applied in order to study effect of initial melt temperature on the microstructure of resultant ribbons. Coarse segregated, elongated areas were observed for low melt ejection temperature, indicating cooling from the miscibility gap region. Increase of the melt ejection temperature up to homogeneous melt region, brought about formation of spherical particles distributed within a homogeneous matrix. Detailed investigations, including X-ray diffraction, differential scanning calorymetry, scanning and transmission electron microscopy, proved amorphous nature of the Fe-rich matrix and crystalline structure of the Cu-rich precipitates. Moreover, presence of the secondary formed spherical particles within primarily precipitated the Cu-rich spheres, was observed.

PL

W pracy przedstawiono mikrostrukturę stopu Fe37Cu25Si13B9Al8Ni6Y2 po szybkim chłodzeniu. Wykazano, że gwałtowne chłodzenie fazy ciekłej (metoda melt spinning) umożliwia wytworzenie in situ kompozytów amorficzno-krystalicznych. W celu określenia wpływu temperatury odlewania stopów na mikrostrukturę taśm, odlewano je z czterech rożnych temperatur z zakresu 1330÷1520°C. Zaobserwowano, że mikrostruktura taśm odlanych z niskiej temperatury charakteryzuje się obecnością dużych, wydłużonych obszarów, co wskazuje, że w trakcie nagrzewania osiągnięto temperaturę z zakresu niemieszalności cieczy. Podwyższenie temperatury odlewania do zakresu jednorodnej cieczy spowodowało, iż w trakcie chłodzenia przez zakres niemieszalności, jedna z faz ciekłych wydziela się w postaci kulistych wydzieleń. Szczegółowe badania, obejmujące rentgenowską analizę fazową, skaningową kalorymetrię różnicową, mikroskopię skaningową i transmisyjną, dowiodły amorficzny charakter osnowy bogatej w Fe oraz krystaliczną strukturę wydzieleń bogatych w Cu. Ponadto w pierwotnie utworzonych cząstkach bogatych w Cu zaobserwowano wtórne kuliste wydzielenia.

9

Nanocrystalization of NiNb(ZrTi)Al metallic glasses

Czeppe T.

Inżynieria Materiałowa

|

2010

|

Vol. 31, nr 3

673-676

EN

The melt spun ribbons of composition Ni58Nbx(ZrTi)1-xAly (x = 5, 10, 20 i 25, y = 3, 7% at.) were investigated. It was found that the crystallization of the amorphous phase proceeded due to two deferent mechanisms in case of the alloys containing less and more than 15 at. % Nb. In both cases different compositions of crystallizing phases and kinetics parameters were found. In case of alloys containing less than 15 at. % Nb, cubic NiTi(Zr) phase crystallized rapidly and completely replaced amorphous phase. In alloys with higher Nb content, a smaller volume, up to 50% of the amorphous phase crystallized in a much slower process, also the resulting phase composition was much complicated. The transformation rates and activation energies determined with use of the Matusita method, invented for the oxide glasses kinetics determination and assuming activation energy evolution during the process are discussed. The Matusita method revealed limited usefulness as it could be applied only to the slower crystallization process.

PL

Badano taśmy amorficzne o składzie Ni58Nbx(ZrTi)1-xAly (x = 5, 10, 20 i 25, y = 3, 7% at.), otrzymane metodą szybkiej krystalizacji na wirującym dysku. Stwierdzono, że faza amorficzna krystalizuje inaczej w przypadku stopów o zawartości Nb mniejszej i większej od 15% at. Stwierdzono inny skład fazowy po krystalizacji i inne parametry kinetyczne. W przypadku szkieł o zawartości Nb mniejszej niż 15% at. gwałtownie krystalizuje faza regularna NiTi(Zr) i całkowicie zastępuje fazę amorficzną. W stopach o wyższej zawartości Nb krystalizacja obejmuje do 50% fazy amorficznej, proces jest znacznie wolniejszy, a skład fazowy po krystalizacji bardziej złożony. Określono i przedyskutowano szybkość przemiany, a także energię aktywacji krystalizacji, w tym ostatnim przypadku stosując równanie Matusity, wynalezione do opisu kinetyki krystalizacji szkieł tlenkowych i zakładające ewolucję energii aktywacji w trakcie procesu. Użyteczność tej metody okazała się ograniczona do wolniejszego procesu krystalizacji.

10

Effect of surface and bulk properties on hydrogen absorption and desorption in NiZr metallic glasses

Vehovszky B., Balla S.

International Journal of Applied Mechanics and Engineering

|

2010

|

Vol. 15, no 2

463-468

EN

After previous examinations in the field of Ni-Zr based hydrogen absorbing glassy alloys, this paper details some surface and bulk processes, which have strong influence in H-charging and discharging properties. It is a usual problem with hydrogen storing materials that imperfect surface and bulk preparation (activation) hinders free movement of hydrogen, thus we can use only a small proportion of theoretical storing capacity. The surface oxide layer is usually a fundamental point: it is often impermeable for hydrogen. It is also true for Ni-Zr based glassy alloys, so the surface of samples has to be activated first by etching in an adequate acetic solution. Another restricting process is the diffusion of H-atoms in bulk metal. This problem is also examined and discussed together with some special measurements that made us able to study the above-mentioned effects easily.

11

The influence of yttrium addition on the GFA of selected iron-based BMG

Pilarczyk W., Mucha A.

Archives of Materials Science and Engineering

|

2010

|

Vol. 44, nr 2

87-95

EN

Purpose: The main aims of this work is the presentation of the influence of yttrium addition on the structure and properties of BMG and the production attempt of chosen Fe-based bulk metallic alloys. Design/methodology/approach: The studies were carried out on Fe- based alloys ingots with the following compositions Fe43Co7Cr15Mo14C15B6, Fe41Co7Cr15Mo14C15B6Y2 and Fe39Co7Cr15Mo14C15B6Y4. Samples were prepared by induction melting of the pure Fe, Co, Cr, Mo, C, B and Y elements in argon atmosphere. The structure was tested with X-ray diffraction. In order to investigate the structure scanning electron microscopy was used. The thermal properties of the alloys were examined by DTA and DSC methods. Findings: Bulk metallic glasses with yttrium addition exhibit high glass forming ability. These materials depending on accurate chemical composition present excellent corrosion resistance, magnetic, electric and mechanical properties. Fe-based materials with yttrium addition are potential materials for industrial applications. Research limitations/implications: It is very difficult to obtain a metallic glass of Fe43Co7Cr15Mo14C15B6, Fe41Co7Cr15Mo14C15B6Y2 and Fe39Co7Cr15Mo14C15B6Y4 alloys. All tested alloys have crystalline structure. Taking into account all the factors affecting the test samples, we can conclude that the received samples have not an amorphous structure for the non-uniform distribution of yttrium in materials. Originality/value: Overall presentation of the yttrium addition influence, the formation and the study of Fe-Co-Cr-Mo-C-B-Y bulk metallic materials.

12

Iron - based bulk amorphous alloys

Babilas R., Nowosielski R.

Archives of Materials Science and Engineering

|

2010

|

Vol. 44, nr 1

5-27

EN

Purpose: The paper presents a structure characterization, thermal and soft magnetic properties analysis of Fe-based bulk amorphous materials in as-cast state and after crystallization process. In addition, the paper gives some brief review about achieving, formation and structure of bulk metallic glasses as a special group of amorphous materials. Design/methodology/approach: The studies were performed on Fe72B20Si4Nb4 metallic glass in form of ribbons and rods. The amorphous structure of tested samples was examined by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) methods. The thermal properties of the glassy samples were measured using differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The magnetic properties contained initial and maximum magnetic permeability, coercive force and magnetic after-effects measurements were determined by the Maxwell-Wien bridge and VSM methods. Findings: The X-ray diffraction and transmission electron microscopy investigations revealed that the studied as-cast bulk metallic glasses in form of ribbons and rods were amorphous. Two stage crystallization process was observed for studied bulk amorphous alloy. The differences of crystallization temperature between ribbons and rods with chosen thickness are probably caused by different amorphous structures as a result of the different cooling rates in casting process. The SEM images showed that studied fractures could be classified as mixed fractures with indicated two zones contained "river" and "smooth" areas. The changing of chosen soft magnetic properties (μr, Bs, Hc) obtained for samples with different thickness is a result of the non-homogenous amorphous structure of tested metallic glasses. The annealing process in temperature range from 373 to 773 K causes structural relaxation of tested amorphous materials, which leads to changes in their physical properties. The qualitative phase analysis from X-ray and TEM diffraction data enables the identification of a single phase of α-Fe for sample annealed at 823 K and a mixture of Fe2B, Fe3B and Fe23B6 and α-Fe phases for samples annealed at temperature of 873 and 923 K. Practical implications: The magnetic properties allow to classify the studied Fe-based glassy alloy for suitable material for electric and magnetic applications. These properties of could be improved by applying the appropriate conditions of heat treatment (crystallization process). Originality/value: The applied investigation methods are suitable to determine the changes of structure, thermal and magnetic properties in function of sample thickness or annealing conditions.

13

Influence of thermal activation on changes of mechanical properties and tensile fracture morphology surface of Ni-base metallic glasses

Griner S., Poloczek T., Nowosielski R.

Archives of Materials Science and Engineering

|

2010

|

Vol. 42, nr 1

13-20

EN

Purpose: The paper presents a structural relaxation and crystallization process of Ni68.7Cr6.6Fe2.65Si7.8B14C0.25 metallic glasses. The Ni68.7Cr6.6Fe2.65Si7.8B14C0.25 metallic glasses were produced by the CBMS method for two different conditions of casting at different cooling rate. Design/methodology/approach: The relaxation and crystallization of Ni68.7Cr6.6Fe2.65Si7.8B14C0.25 metallic glasses by methods: mechanical tests, scanning electron microscopy (SEM) and internal friction (IF) were studied. Findings: The investigation showed that conditions of vitrification (different, but higher than critical cooling rate) influence on different course of elementary structural relaxation processes during thermal activation. Research limitations/implications: The differences in temperature of the beginning of elementary relaxation processes and crystallization processes of alloy, in relation to strip thickness were disclosed. Practical implications: The course of relaxation processes can be used for analysis of thermal stability of metallic glasses. Originality/value: The paper presents those conditions of vitrification influence on different course structural relaxation processes during thermal activation.

14

Structure and properties of selected Fe-based metallic glasses

Nowosielski R., Babilas R.

Journal of Achievements in Materials and Manufacturing Engineering

|

2009

|

Vol. 37, nr 2

332-339

EN

Purpose: The paper presents a structure characterization, thermal and soft magnetic properties of Fe-based bulk amorphous materials in as-cast state and after crystallization process. Design/methodology/approach: The studies were performed on Fe72B20Si4Nb4 metallic glass in form of ribbons and rods. The amorphous structure of tested samples was examined by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) methods. The thermal properties of the glassy samples were measured using differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The soft magnetic properties examination of tested material contained magnetic permeability and magnetic after-effects measurements. Findings: The X-ray diffraction and transmission electron microscopy investigations revealed that the studied as-cast materials were amorphous. Broad diffraction halo could be seen for all tested samples, indicating the formation of a glassy phase with the diameters up to 2 mm. The fracture surface of rod samples appears to consist of two different zones, which probably inform about different amorphous structures of studied glassy materials. A two stage crystallization process was observed for studied alloy. The first stage of crystallization corresponding to the partial crystallization of á-Fe phase was followed by the formation of iron borides. It has shown that appropriate increasing of annealing temperature, significantly improved soft magnetic properties of examined alloy. Practical implications: The studied Fe-based metallic glass has good glass-forming ability and thermal stability for casting in form of ribbons and rods. The soft magnetic properties of studied alloy could be improved by applying the appropriate conditions of heat treatment (crystallization process). Originality/value: The applied investigation methods are suitable to determine the changes of structure in function of sample thickness and the improvement of its magnetic properties after crystallization in comparison with as-cast state.

15

Formation and structure of Co50Cr15Mo14C15B6 bulk metallic glasses

Nowosielski R., Witrak A.

Archives of Materials Science and Engineering

|

2009

|

Vol. 36, nr 1

28-33

EN

Purpose: In the present paper thermal stability and structure of Co50Cr15Mo14C15B6 (numbers indicate at.%) glassy alloys were investigated. Design/methodology/approach: The following experimental techniques were used: scanning electron microscopy (SEM) and X-ray diffraction (XRD) phase analysis method to the test the structure. The thermal properties associated with crystallization temperature of the glassy samples were measured using differential thermal analysis and differential scanning calorimetry. Findings: The structural studies revealed an amorphous structure for the rods with thicknesses up to 3 mm, regardless of their thickness. Research limitations/implications: During thermal activation of metallic glasses two processes can be distinguished: structural relaxation and complex relaxation process of the alloy. Practical implications: The Co-rich amorphous alloys have attracted great interest for a basic research on the materials as well as for variety application. Originality/value: The obtained results confirm the utility of applied investigation methods in the thermal and structure analysis of examined amorphous alloys.

16

Thermal and magnetic properties of selected Fe-based metallic glasses

Nowosielski R., Babilas R., Ochin P., Stokłosa Z.

Archives of Materials Science and Engineering

|

2008

|

Vol. 30, nr 1

13-16

EN

Purpose: The work presents a thermal stability characterization and soft magnetic properties analysis of selected Fe-based metallic glasses. Design/methodology/approach: The studies were performed on ribbons prepared by the planar flow casting technique, which is a method of continuous casting of the liquid alloy on a surface of turning copper based wheel. The methods of X-ray diffraction were used for the qualitative phase analysis. The thermal properties associated with crystallization temperature of the glassy alloys were measured using the differential thermal analysis. The magnetic properties were determined by the Maxwell-Wien bridge, fluxometer and VSM methods. Findings: The studied Fe72B20Si4B4 and Fe36Co36B19Si5Nb4 metallic glasses in as-cast state were fully amorphous. The Curie temperature (Tc) for Fe72B20Si4B4 alloy has a value of 582 K and Fe36Co36B19Si5Nb4 has higher Tc, which has a value of 605 K. The obtained magnetic properties allow to classify the studied amorphous alloys in as-cast state as soft magnetic materials. The coercive field of tested alloys has a value about 8 A/m. The maximum magnetic permeability of Fe72B20Si4B4 alloy (!max = 21500) is much higher than Fe36Co36B19Si5Nb4 metallic glasses (max = 3200). Similarly, saturation magnetization of Fe72B20Si4B4 alloy (Bs = 1.04 T) is higher than Fe36Co36B19Si5Nb4 (Bs = 0.99 T) amorphous alloy. Practical implications: The studied glassy alloys are suitable materials for many electrical application in different elements of magnetic circuits and for manufacturing of sensors and precise current transformers. Originality/value: The obtained results confirm the utility of applied investigation methods in the thermal and magnetic properties analysis of examined amorphous alloys.

17

Shielding of electromagnetic fields by mono- and multi-layer fabrics made of metallic glasses with Fe and Co matrix

Nowosielski R., Griner S.

Journal of Achievements in Materials and Manufacturing Engineering

|

2007

|

Vol. 20, nr 1-2

45-54

EN

Purpose: In the work, influence of chemical composition, as well as magnetic and electric properties on ability of metallic glass screens for shielding of not ionizing electromagnetic fields were analyzed. Design/methodology/approach: The groups of amorphous metallic alloys with iron, iron and nickel and cobalt matrix were selected for research. Samples of afore-mentioned metallic glasses were examined from the point of view of structure, magnetic, electric and mechanical properties. Findings: There is possibility of utilization of metallic amorphous materials for screens of not ionizing, electromagnetic fields especially in range of broad-band multi-layers screens with high efficiency of shielding in wide range of frequencies. Research limitations/implications: Very good magnetic properties and parallel low electric conductivity of metallic glasses are not enough for construction of multi-layer broadband screen. Therefore for constructing broadband screen, which would attenuate much better in wider range of frequencies, we should seek solutions in multi layers systems consisting of metallic glass fabrics, layers of large conductivity materials and nonmagnetic isolating layers. Problems of determining the number of layers, individual thickness of layer, materials in relation to optimum costs of multi-layers screen metallic glasses are unsolved. Practical implications: Attenuation of metallic glass screens show very high possiblilities of metallic glasses in solution of problem of shielding electromagnetic fields. Originality/value: There are two general direction of improvement of suppression efficiency of electromagnetic fields screens: research of new constructions of elastic screens, and investigation of new materials for screens join higher magnetic properties at high conductivity. In this second area, any possibilities exist in metallic nanomaterials in form of tapes and nanocomposites consisting magnetic powders with amorphous and nanocrystalline structure.

18

Microstructure investigations of Co-Si-B alloy after milling and annealing

Nowosielski R., Babilas R., Dercz G., Pająk L.

Journal of Achievements in Materials and Manufacturing Engineering

|

2007

|

Vol. 23, nr 1

59-62

EN

Purpose: The work presents the microstructure characterization of Co77Si11,5B11,5 metallic glass after high-energy ball milling and heat treatment processes. Design/methodology/approach: The studies were performed on ribbon prepared by melt spinning and this ground in high-energy vibratory ball mill. The tested ribbon and obtained powders were also annealed in specified heat treatment conditions. The morphology of the powder particles of milled ribbon was analyzed by using the confocal laser scanning microscope. The methods of X-ray diffraction were used for the qualitative phase analysis. The parameters of the individual diffraction line profiles were determined by PRO-FIT Toraya procedure. The average crystallite sizes and lattice distortions for Co phase were estimated using Williamson-Hall method. Findings: The studied Co77Si11,5B11,5 metallic glass in annealed state contains hexagonal Co crystalline phases emerged in amorphous matrix. The crystallite size of Co phase in as-cast sample lies in nanoscale. After annealing process the crystallite size increases to 72 nm and diminishes to 46 nm in the powder sample after 30 hours of milling. The milling causes decrease of the crystallite size and increase of lattice distortions of crystalline phase. The powder particles after 30 hours of milling are of spherical shape. Practical implications: The powder particles obtained after milling process of Co-based metallic glass could be suitable components in production of ferromagnetic nanocomposites. Originality/value: The obtained results confirm the utility of applied investigation methods in the microstructure analysis of powder materials with nanocrystalline phases.

19

Microstructure studies of ball milled and vacuum hot pressed NiZrTiAl powders

Dutkiewicz J., Maziarz W., Litynska L., Molnárová M., Kováčová A.

Archives of Materials Science and Engineering

|

2007

|

Vol. 28, nr 11

645-648

EN

Purpose: To determine microstructure and hardness of hot pressed mechanically alloyed MA NiZrTiAl powders well known as a good glass formers. Design/methodology/approach: Powders has been ball milled r 40 hours starting from pure elements. Changes of particle's size and crystallographic structure of nanocrystals embedded in the amorphous matrix during milling has been determined using High Resolution Transmission Electron Microscopy HRTEM. Findings: The MA particles first grow, then decrease after 40 hours of milling, when powders possess amorphous structure. HRTEM studies of powders allowed to reveal small nanocrystals of NiTi2 within milled powders which were not detected using X-Ray diffraction. The powders show crystallization peak at temperature Tx near 553*C. Consolidation of powders was performed under vacuum using uniaxial hot pressing method at temperature slightly below Tx. Mean microhardness was determined near 430 HV and the mean Young's modulus as 81 GPa. Practical implications: It was shown a possibility of hot densification in vacuum of amorphous Ni base alloys allowing to obtain bulk amorphous compacts with embedded nanocrystals. Originality/value: The size and structure of nanmocrystals within the amorphous matrix after MA and after hot vacuum densification has been determined. The microhardness and Young's modulus of compacts show perspectives of application of such materials.

20

Wpływ składu chemicznego i sposobu przygotowania stopu (NiCu)ZrTiAlSi na amorficzność i mikrostrukturę

Czeppe T., Sypień A., Anastasova S., Latuch J., Ochin P.

Inżynieria Materiałowa

|

2006

|

Vol. 27, nr 3

127-130

PL

Szkła metaliczne charakteryzują się brakiem zakresu odkształcenia plastycznego. Zwiększonego zakresu odkształcenia plastycznego oczekuje się w przypadku struktury kompozytowej: amorficznej matrycy z dendrytycznymi cząstkami faz odkształcalnych. Praca poświecona stopowi na bazie niklu o składzie nominalnym (Ni1-0.29Cu0.29)58Zr18Ti13Al6Si5 (%at.). Stop badany był w postaci taśm zestalanych na wirującym walcu i próbek masywnych, chłodzonych z różną szybkością. Faza amorficzna podlega devitryfikacji w temperaturze Tg 583oC, temperatura krystalizacji Tx wynosi 579oC, zakres cieczy przechłodzonej Tx-Tg 41oC a parametr Tg/Tl 0.64. W fazie amorficznej występują kryształy o składzie zbliżonym do matrycy amorficznej, wzbogaconym w Al i Si a o obniżonej zawartości Ni i Cu. Tworzą się one w trakcie zestalenia fazy ciekłej. W zależności od szybkości chłodzenia stop wykazuje zdolność do tworzenia mikrostruktury kompozytu amorficznego. Dendrytyczne kryształy wykazują skład (Ni4Cu)53(Zr2TiAl)40Si7 i Ni(Cu)40-Zr(Ti)35Si25.

EN

Metallic glasses are characterized by the lack of ductility. Enhanced plastic deformation range is expected in case of composite structure consisting in amorphic matrix with dendritic particles of ductile phases inside. The paper concerns properties of the Ni-based alloy of nominal composition (Ni1-0.29Cu0.29)58Zr18Ti13Al6Si5 (%at.). The alloy was investigated in the form of ribbons prepared by melt spinning and massive samples, cooled with the different rates. Devitrification of the amorphic phase proceeds at Tg 583oC, crystallization temperature Tx is 579oC, overcooled liquid range Tx-Tg - 41oC, GFA Tg/Tl - 0.64. Some separated crystals were formed during solidification in the amorphous phase. The composition of the crystals is similar to the amorphous matrix but enriched in Al and Si and depleted in Ni and Cu. Depending on the cooling rate the alloy reveals ability to form amorphous composite microstructure. The composition of the dendrites is near to (Ni4Cu)53(Zr2TiAl)40Si7 i Ni(Cu)40Zr(Ti)35Si25 phases.