EFFECT OF COPPER ADDITIVES ON IRREVERSIBLE MELTING IN [{(Fe0.5Co0.5)0.75B0.2Si0.05}96Nb4]100-xCux, x ≤ 3, ALLOYS

2011 ◽  
Vol 10 (04n05) ◽  
pp. 1013-1017
Author(s):  
T. KARAN ◽  
S. RAM ◽  
M. STOICA ◽  
J. ECKERT
Keyword(s):  
Melting Point ◽  
Amorphous Alloys ◽  
Amorphous Structure ◽  
Slow Heating ◽  
Differential Scanning Calorimetric ◽  
Bulk Amorphous Alloys ◽  
Heating And Cooling ◽  
Effect Of Copper ◽  
Ferromagnetic Bulk ◽  
Mould Casting

Iron and cobalt based ferromagnetic bulk amorphous alloys have received considerable interest nowadays in view of their useful properties for wide spread applications in magnet technology, shape memory alloys, high frequency communications at low power loss, and other devices. In this purview, here we report synthesis and thermal properties of bulk amorphous alloys [{( Fe 0.5 Co 0.5)0.75 B 0.2 Si 0.05}96 Nb 4]100-x Cu x (x = 0, 1, 2, and 3). A copper mould casting of molten alloy was used to obtain a vitrified alloy in form of thin rods (1–2 mm diameter). Amorphous structure retains at a cooling rate as low as 100 K/s in argon atmosphere. Heat out-put measured in terms of a differential scanning calorimetric signal during heating and cooling cycles of these alloys demonstrate irreversibility in a compositional dependent melting point, which follows the glass transition temperature and successive crystallization. The irreversibility persists in this specific example of the bulk amorphous alloys even on sufficiently slow heating or cooling rates such as 0.33 K/s in argon. The copper inclusion tailors the melting point, the enthalpy of the fusion, and other thermodynamic parameters. Results are analyzed in corroboration to the magnetic properties.

Ferromagnetic bulk amorphous alloys

1998 ◽  
Vol 29 (7) ◽  
pp. 1779-1793 ◽  
Author(s):  
Akihisa Inoue ◽  
Akira Takeuchi ◽  
Tao Zhang
Keyword(s):  
Amorphous Alloys ◽  
Bulk Amorphous Alloys ◽  
Ferromagnetic Bulk

scholarly journals Newtonian Flow in Bulk Amorphous Alloys

1999 ◽  
Vol 601 ◽  
Author(s):  
J. Wadsworth ◽  
T.G. Nieh
Keyword(s):  
Amorphous Alloys ◽  
Sliding Friction ◽  
Structural Evolution ◽  
Supercooled Liquid ◽  
Amorphous Structure ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Structural Components ◽  
Bulk Amorphous Alloys ◽  
Near Net Shape

AbstractBulk amorphous alloys have many unique properties, e.g., superior strength and hardness, excellent corrosion resistance, reduced sliding friction and improved wear resistance, and easy formability in a viscous state. These properties, and particularly easy formability, are expected to lead to applications in the fields of near-net-shape fabrication of structural components. Whereas large tensile ductility has generally been observed in the supercooled liquid region in metallic glasses, the exact deformation mechanism, and in particular whether such alloys deform by Newtonian viscous flow, remains a controversial issue. In this paper, existing data are analyzed and an interpretation for the apparent controversy is offered. In addition, new results obtained from an amorphous alloy (composition: Zr–10Al–5Ti–17.9Cu–14.6Ni, in at. %) are presented. Structural evolution during plastic deformation is particularly characterized. It is suggested that the appearance of non-Newtonian behavior is a result of the concurrent crystallization of the amorphous structure during deformation.

Establishing the Glass Forming Ability of Ferromagnetic Bulk Amorphous Alloys Using a Mathematical Model Based on the Chemical Composition

2012 ◽  
Vol 188 ◽  
pp. 11-14
Author(s):  
Dragoş Buzdugan ◽  
Cosmin Codrean ◽  
Mircea Vodǎ ◽  
Viorel Aurel Şerban
Keyword(s):  
Mathematical Model ◽  
Chemical Composition ◽  
Amorphous Alloys ◽  
Primary Crystallization ◽  
Glass Forming Ability ◽  
Bulk Amorphous Alloys ◽  
Glass Forming ◽  
Ferromagnetic Alloys ◽  
The Difference ◽  
Ferromagnetic Bulk

This paper presents a mathematical model that describes the influence of the chemical composition on the glass forming ability of ferromagnetic alloys. Glass forming ability is given by the difference between the glass transition temperature and the primary crystallization temperature of the alloy. The glass forming ability is better as long this difference has a higher value. These temperatures were determined using differential thermal analysis.

scholarly journals The Kinetic Peculiarities of the Nanocrystallization of Amorphous Alloys Fe84Nb2B14, which are Doped by Rare Earth Metals

2017 ◽  
Vol 18 (1) ◽  
pp. 122-128 ◽  
Author(s):  
L. Boichyshyn ◽  
M.-O. Danyliak ◽  
B. Kotur ◽  
T. Mika
Keyword(s):  
Amorphous Alloys ◽  
Rare Earth Metals ◽  
Amorphous Structure ◽  
Differential Scanning Calorimetric ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dimensional Diffusion ◽  
Diffusion Controlled ◽  
Dsc Method ◽  
Xrd Method

The thermal stability and crystallization of the Fe82Nb2B14RE2 (RE = Y, Gd, Tb, Dy) amorphous alloys were investigated by differential scanning calorimetric (DSC) method. By X-ray diffraction (XRD) method has been established that the initial AMA have amorphous structure. The RE alloying of Fe82Nb2B14RE2 amorphous alloys increase the nanocrystallization temperatures for ~ 110 K and activation energies of crystallization for ~ 330 kJ/mol. The Avrami constant was found to be 1.86 for Fe84Nb2B14 at 703 K, 1.17 for Fe82Nb2B14Y2 at 813 K, 1.36 for Fe82Nb2B14Gd2 at 808 K, 1.76 for Fe82Nb2B14Tb2 at 808 K and 1.92 for Fe82Nb2B14Dy2  at 808 K. Two-dimensional diffusion controlled growth mechanism with decreasing nucleation rate was observed in the alloys.

Synthesis and Properties of Ferromagnetic Bulk Amorphous Alloys

1998 ◽  
Vol 554 ◽  
Author(s):  
A. Inoue ◽  
T. Zhang ◽  
H. Koshiba ◽  
T. Itoi
Keyword(s):  
Thermal Stability ◽  
Amorphous Alloy ◽  
Rapid Solidification ◽  
Amorphous Alloys ◽  
Supercooled Liquid ◽  
Soft Magnetic Materials ◽  
Bulk Amorphous Alloys ◽  
Application Fields ◽  
Ferromagnetic Bulk ◽  
Alloy Systems

Since an amorphous phase in Au-Si system was synthesized for the first time by rapid solidification in 1960[1], a large number of amorphous alloys have been prepared by various rapid solidification techniques. As the main amorphous alloy systems, one can list up the noble metal-, Fe-, Co-, Ni-, Ti-, Zr-, Nb-, Mo-, lanthanide(Ln)-, Al- and Mg-based alloys. Among these alloy systems, Fe-[2], Co-[2] and Al-[3]based amorphous alloys have been used in application fields of magnetic and high specific-strength materials. Thus, Fe- and Co-based amorphous alloys have gained the most important position as engineering amorphous alloys. When special attention is paid to Fe-based amorphous alloys, Fe-P-C alloys were synthesized in 1967[4] as the first Febased amorphous alloy. Subsequently, engineering important (Fe,Co)-Si-B amorphous alloys have been developed in 1974[5][6], followed by the formation of (Fe,Co,Ni)-(Cr,Mo,W)-C in 1978[7], (Fe,Co,Ni)-(Zr,Hf) in 1980[8] and then (Fe,Co,Ni)-(Zr,HfNb)-B amorphous alloys in 1981[9]. The (Fe,Co)-Si-B amorphous alloys have been used in many application fields as soft magnetic materials[2]. However, after 1981, nobody have succeeded in finding a new amorphous alloy in Fe- and Co-based systems by rapid solidification from liquid phase. Besides, all these amorphous alloys have serious disadvantages that high cooling rates above 105 K/s are required for glass formation and the resulting sample thickness is limited to less than about 50 μm[ 10]. Great efforts have been devoted to find Fe- and Co-based amorphous alloys with a high thermal stability of supercooled liquid against crystallization and a high glass-forming ability (GFA). Very recently, we have succeeded in finding new ferromagnetic bulk amorphous alloys with critical sample thicknesses ranging from I to 15 mm in Fe-(AI,Ga)-(P,C,B,Si)[11]-[14], (Fe,Co,Ni)-(Zr,IHf,Nb)- B[15]-[17], (Fe,Co)-(Zr,Hf)-(Nb,Ta)-(Mo,W)-B[18], (Fe,Co)-Ln-B[19] (Ln=lanthanide metal) and (Nd,Pr)-Fe-Al[20]-[22] systems. In this review, we present the formation, thermal stability, mechanical strength and magnetic properties of these new ferromagnetic bulk amorphous alloys.

scholarly journals Effect of Heat Treatment on Magnetic Properties of Bulk Amorphous Alloys Fe63+xCo10Y7-xB20 (x=0, 2)

2019 ◽  
Vol 70 (2) ◽  
pp. 724-729
Author(s):  
Jerzy Wyslocki ◽  
Mateusz Talar
Keyword(s):  
Heat Treatment ◽  
Magnetic Properties ◽  
Thermal Treatment ◽  
Curie Temperature ◽  
Amorphous Alloys ◽  
Magnetization Vector ◽  
Amorphous Structure ◽  
Bulk Amorphous Alloys ◽  
Research Material ◽  
Xrd Studies

This paper presents the results of tests on amorphous alloys Fe65Co10Y5B20, Fe63Co10Y7B20 in the state after solidification and after thermal treatment. The thermal treatment was performed below the crystallization temperature and above the Curie temperature (750K/25 min). The samples for the investigation had the shape of rods with a diameter of 1 mm and a length of 20 mm. The structure and magnetic properties were studied for the research material. The structure was investigated using XRD and the magnetic properties using VSM and FERROTESTER. XRD studies showed that the samples both in solidified state and after thermal treatment had an amorphous structure. The losses for the re-magnetization of the tested samples were comparable to those for commercially used FeSi materials. The process of magnetization in the vicinity of the area called the approach to ferromagnetic saturation is associated with all tested samples with rotation of the magnetization vector near free volumes. An interesting result of the conducted research is that not always a thermal treatment made on general principles leads to improvement of magnetic.

Effect of Co and Cu Alloying on Nd-Fe-Al Based Bulk Amorphous Alloys

2000 ◽  
Vol 343-346 ◽  
pp. 97-102 ◽  
Author(s):  
G.J. Fan ◽  
Jürgen Eckert ◽  
W. Löser ◽  
S. Roth ◽  
Ludwig Schultz
Keyword(s):  
Amorphous Alloys ◽  
Bulk Amorphous Alloys

Crystallization and fracture behavior of the Zr65−xAl7.5Cu17.5Ni10Six bulk amorphous alloys

2005 ◽  
Vol 89 (1) ◽  
pp. 122-129 ◽  
Author(s):  
J.S.C. Jang ◽  
Y.W. Chen ◽  
L.J. Chang ◽  
H.Z. Cheng ◽  
C.C. Huang ◽  
...  
Keyword(s):  
Amorphous Alloys ◽  
Fracture Behavior ◽  
Bulk Amorphous Alloys

scholarly journals Li-Nafion Membrane Plasticised with Ethylene Carbonate/Sulfolane: Influence of Mixing Temperature on the Physicochemical Properties

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1150
Author(s):  
Aigul S. Istomina ◽  
Tatyana V. Yaroslavtseva ◽  
Olga G. Reznitskikh ◽  
Ruslan R. Kayumov ◽  
Lyubov V. Shmygleva ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Ethylene Carbonate ◽  
Membrane Integrity ◽  
Amorphous Structure ◽  
Nafion Membrane ◽  
Polymer Gel ◽  
Scanning Calorimetry ◽  
Practical Applications ◽  
Heating And Cooling ◽  
Solvent Uptake

The use of dipolar aprotic solvents to swell lithiated Nafion ionomer membranes simultaneously serving as electrolyte and separator is of great interest for lithium battery applications. This work attempts to gain an insight into the physicochemical nature of a Li-Nafion ionomer material whose phase-separated nanostructure has been enhanced with a binary plasticiser comprising non-volatile high-boiling ethylene carbonate (EC) and sulfolane (SL). Gravimetric studies evaluating the influence both of mixing temperature (25 to 80 °C) and plasticiser composition (EC/SL ratio) on the solvent uptake of Li-Nafion revealed a hysteresis between heating and cooling modes. Differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) revealed that the saturation of a Nafion membrane with such a plasticiser led to a re-organisation of its amorphous structure, with crystalline regions remaining practically unchanged. Regardless of mixing temperature, the preservation of crystallites upon swelling is critical due to ionomer crosslinking provided by crystalline regions, which ensures membrane integrity even at very high solvent uptake (≈200% at a mixing temperature of 80 °C). The physicochemical properties of a swollen membrane have much in common with those of a chemically crosslinked polymer gel. The conductivity of ≈10−4 S cm−1 demonstrated by Li-Nafion membranes saturated with EC/SL at room temperature is promising for various practical applications.

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