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1.
In this work, we present a systematic study on the crystallization kinetics and the magnetic properties of melt-spun Fe80B10Si10 ? xGex (x = 0.0 ? 10.0) amorphous alloys. The activation energy for crystallization, determined by differential scanning calorimetry, displayed a strong dependence on the Ge content, reflecting a deleterious effect on the alloys' thermal stability and their glass forming ability with increasing Ge concentration. On the other hand, the alloys exhibited excellent soft magnetic properties, i.e., high saturation magnetization values (around 1.60 T), alongside Curie temperatures of up to 600 K. Complementary, for increasing Ge substitution, the ferromagnetic resonance spectra showed a microstructural evolution comprising at least two different magnetic phases corresponding to a majority amorphous matrix and to Fe(Si, Ge) nanocrystallites for x ≥ 7.5. 相似文献
2.
Amorphous Fe67?xC10B9Mo7+xCr4W3 (x = 1–7 at.%) plates with 0.64 mm thickness were prepared by copper mold casting. The thermal properties and microstructural development during heat treatments were investigated by a combination of differential scanning calorimetry, differential thermal analysis, and X-ray diffraction. The glass forming ability (GFA) and activation energy for crystallization have a distinct dependence on Mo content. Fe62C10B9Mo12Cr4W3 was the best glass former in this study, demonstrating a supercooled liquid region, ΔTx = 51 K, and an activation energy for crystallization, Q = 453 kJ/mol. The GFA of alloys in this system was governed by elastic strain optimization resulting directly from the variation in Mo content. Heat treatments were performed to demonstrate resistance to crystallization under typical processing conditions. Alloys in this system exhibited a three phased evolution during crystallization. A second set of heat treatments was performed to identify each phase. An analysis of phase evolution revealed a distinct dependence of phase evolution with stepwise substitution of Mo for Fe in this system. 相似文献
3.
Bulk Fe80?xMoxP10C7.5B2.5 (x = 5–10 at.%) metallic glasses are synthesized by copper mold casting, which have a critical diameter up to 3 mm, fracture strength over 3000 MPa, plastic strain up to 2.5% and saturation magnetization reaching 1.1 T. Results show that the glass forming ability and strength increase with increasing Mo content, while the plasticity and saturation magnetization do otherwise. These Mo content dependent properties are illuminated with the atomic interactions in the alloys that could be strengthened by suitable addition of Mo element. The effects of Mo on the properties of the alloys imply that proper Mo element should be chosen in designing Fe-based glassy alloys with desired properties. 相似文献
4.
In the present research work, thermal stability, magnetic properties and microhardness of Fe72B19.2Si4.8M4 (M = Ta or Y) amorphous ribbons obtained by chill block melt-spinning technique are reported. The crystallization temperatures resulted as high as 1129 K (for M = Ta) and of 1167 K (for M = Y), which indicate a considerable thermal stability for both alloys. On the other hand, the saturation polarization (μ0Ms) together with the Curie temperature (Tc) also showed excellent combination of values, with 0.95 ± 0.12 T and 586 ± 8 K, respectively (for the Ta-containing alloy) and of 1.55 ± 0.18 T and 698 ± 6 K, respectively (for the Y-containing alloy). Additionally, the Vickers microhardness exhibited values over 1100 kg/mm2 for both alloys. 相似文献
5.
Z.L. Long C.T. Chang Y.H. Ding Y. Shao P. Zhang B.L. Shen A. Inoue 《Journal of Non》2008,354(40-41):4609-4613
Fe-based ferromagnetic [(Fe1?xNix)0.75B0.2Si0.05]96Nb4 (x = 0, 0.2 and 0.4) bulk glassy alloys (BGAs) with a diameter of 2 mm were prepared by copper mold casting. The corrosion behavior of glassy alloy rods obtained was investigated in 0.5 M NaCl, 0.5 M NaOH and 0.5 M H2SO4 aqueous electrolytes, respectively, using weight loss and electrochemical polarization measurements. It was found that the corrosion rates significantly decrease with an increase in Ni content in all examined solutions. The Ni-containing BGAs are spontaneously passivated with wide passive regions and low passive current densities in NaCl and NaOH solutions, but exhibit the active–passive–transpassive behavior in H2SO4 solution. The partial substitution of Ni for Fe results in a considerable improvement on the corrosion resistance of [(Fe1?xNix)0.75B0.2Si0.05]96Nb4 BGAs, because of the structural and chemical homogeneousness of the amorphous phase and the effect of Ni on promoting the formation of a passive film. Besides their high glass-forming ability (GFA), excellent soft-magnetic properties and good mechanical performance, which have been reported before, these FeNi-based BGAs also feature rather high corrosion resistance. 相似文献
6.
The internal friction and the shear modulus of the amorphous Pd80–Si20–, Fe80–P13–C7 and Fe50–Ni33–P12–C5 alloys have been measured at about 0.5 Hz over a temperature range from room temperature to about 550°C. The internal friction rises steeply with temperature and shows maxima around the crystallization temperature. The activation energy for the steeply rising internal friction has been estimated by the two different procedures; from the shift of the curve by the frequency change and from the slope of the In Q?1 versus 1/T plot. The two values are very different, which indicates the existence of a wide distribution of activation energies. Crystallization of the amorphous alloys resulted in an increase of about 30% in the shear modulus. 相似文献
7.
B.F.O. Costa V.S. Amaral G. Le Caër M.E. Braga M.M. Amado D.L. Rocco J.B. Sousa 《Journal of Non》2008,354(47-51):5287-5289
The influence of the formation conditions of the sigma phase in an equiatomic FeV alloy on the magnetic and electric transport properties is studied. It is found that a sigma phase sample with higher resistivity (subject to a previous long annealing) has a much sharper magnetic transition than one formed after a shorter heat treatment and quenching, although both have very similar magnetic moments and ferromagnetic transition temperatures (Tc ~ 15 K from minimum dM/dT). 相似文献
8.
In this work, the variation of the glass-forming ability (GFA) in Fe–Co–Cr–Mo–C–B–Y alloy system with Co addition has been investigated from the viewpoints of non-isothermal viscosity and free volume. The best GFA for the alloy containing 7% Co is found to closely relate with its highest viscosity, and the minimum sizes and lowest concentrations of the intermediate and largest open volumes. The results may provide more insights into the formation mechanism of metallic glasses. 相似文献
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10.
Sandip P. Harimkar Sameer R. Paital Ashish Singh Robert Aalund Narendra B. Dahotre 《Journal of Non》2009,355(43-44):2179-2182
Fabrication of Fe-based amorphous alloy using spark plasma sintering (SPS) process has been reported. Fully amorphous compacts with ~95% relative density were successfully sintered at temperature about 100 °C lower than glass transition temperature (Tg: 575 °C). Formation of crystalline Fe23(C, B)6 phases within near-fully dense (~99%) amorphous matrix is observed at sintering temperatures (>550 °C) close to glass transition temperature. Microstructure evolution in sintered compacts indicated that density, degree of crystallinity, and mechanical properties can be effectively controlled by optimizing SPS parameters. 相似文献
11.
The kinetics of transformation behavior of roller-quenched amorphous Pd83Si17 and Pd80Si20 alloys after linear and isothermal heating is reported. The transformation was examined with electron microscopy, electron diffraction and electrical resistivity measurement. The crystallization of amorphous alloys with 17 at% Si begins with metastable ordered fcc solid solution. The ordered fcc solution is transformed to a ordered metastable phase with, probably, orthorhombic structure. The crystallization of amorphous alloys with 20 at% Si begins by formation of spherulites with lamellar structure. Using electron diffraction we found that spherulites consist of two phases - orthorhombic Pd3Si silicide and Pd-rich silicide. From resistivity measurements, activation energies of 28.5 kcal/mol for Pd83Si17 and 80 kcal/mol for Pd80Si20, respectively, were calculated. 相似文献
12.
J.S. Blázquez M. Millán C.F. Conde V. Franco A. Conde S. Lozano-Pérez 《Journal of Non》2008,354(47-51):5135-5137
Specific heat at constant pressure, CP, was measured on amorphous, nanocrystalline and fully crystalline samples of Fe60Co18Nb6B16 alloy. Magnetic and calorimetric measurements agree, describing a continuously decreasing Curie temperature of the amorphous phase. A clear enhancement of CP over the Dulong–Pettit limit has been observed (from 14% to 25 %). Part of the enhancement is due to magnetic (mainly amorphous phase) and electronic contributions, although an excess volume can be inferred from the high value of the slope of CP versus temperature. 相似文献
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14.
《Journal of Non》2006,352(52-54):5618-5632
A continuous network model of xWO3–(1 − x)TeO2 glasses is developed, based on quantum-chemical calculation and Raman spectra analysis, in order to relate the structural and vibrational properties with glass composition. The tungstate–tellurite glass network is shown to be formed mainly by structural units of three types, TeO4 trigonal bipyramids, OTeO2 trigonal pyramids, and WO6 octahedra with OW double bonds. Most of the W atoms are found to be incorporated into single OWO5 octahedra, with no more than several percents of these atoms occurring in 2[OWO5] paired tungstate centers. The structural and vibrational properties of tungstate–tellurite glasses of several compositions are analyzed by application of the model and a novel interpretation of the Raman spectra is suggested. 相似文献
15.
The application of T–x–y phase diagram for the control of the crystal composition of alloy crystals during Bridgman growth is illustrated using (Pb1−xSnx)1−δSe1+δ solid solutions as an example. Within the framework of the proposed approach, the axial segregation can be minimised if the feed composition is chosen in the regions of phase diagram where the iso-mole-fraction lines are perpendicular to isotherms. For the system Pb–Sn–Se the component distribution in crystals grown from a melt with δ=0, a Se-rich melt (δ>0) and a metal-rich melt (δ<0) are discussed. Uniform crystals with x=(0.03–0.15)±0.01 can be obtained from Se-rich melt (Se enrichment is 12–5 at%Se, T=1280–1200 K). The use of metal-rich melt allows obtaining crystals with moderate segregation of 3–5 mol% SnSe for x=0.13–0.23 at 3–9 at% of metal enrichment and T=1270–1200 K and for x=0.35–0.45 at 25–35 at% of metal enrichment and T=1120–1050 K. 相似文献
16.
Material and electronic properties of Ni–Nb–Zr–H glassy alloys were investigated as a function of the rotating wheel speed in the amorphous ribbon-preparation method. Increase in density and amorphous colony size indicates that the degree of amorphousness increases with increase in the rotating speed. Supercooling, which reached by rotating wheel speed of 10,000 rpm (104.7-m/s), of the molten alloy produces a ballistic conductor with electrical conductivity of about 0.1 nΩ cm (× 10? 9 Ω cm, 0.01% of silver (1.62 μΩ cm)) for (Ni0.36Nb0.24Zr0.40)94.6 H5.4 glassy alloy and a room-temperature discrete Coulomb oscillation for (Ni0.36Nb0.24Zr0.40)91.6H8.4 glassy alloy. The increase in degree of amorphousness by supercooling induces uniformity of cluster morphology. 相似文献
17.
The effect of rare-earth elements on the plasma etching behavior of oxide glasses were investigated to develop the window glass for a plasma processing chamber in the semiconductor industry. Aluminosilicate glasses with various rare-earth elements (Y, Gd and La) were prepared and their optical transmittance and plasma etching depth were evaluated. The plasma etching behavior of the glasses was estimated by X-ray photoelectron spectroscopy analysis at the fluorine plasma exposure surface of the glasses. The rare-earth element in the glass was highly related to various properties such as density, molar volume, mechanical properties and plasma etching depth. The cationic field strength of the rare-earth element more strongly affected the plasma etching depth of the glasses than the sublimation point of the fluorine compounds and this may be related to the plasma etching condition. 相似文献
18.
V. V. Akhnazarova L. A. Shilkina O. Yu. Kravchenko L. A. Reznichenko 《Crystallography Reports》2011,56(2):282-288
The effect of closed porosity (2 and 10%) on the sequence phase transitions in lead-free ceramics (based on sodium niobate) in the temperature range of 25–700°C has been studied. The phase patterns in relatively dense and highly porous ceramics are found to differ. 相似文献
19.