scholarly journals CRYSTALLIZATION PROCESSES OF SOME AMORPHOUS ALLOYS

2020 ◽  
Vol 1 (2) ◽  
pp. 35-38
Author(s):  
W.Q. Yua ◽  
L.P. Lu
Keyword(s):  
Magnetic Property ◽  
Amorphous Alloys ◽  
Melt Spinning ◽  
Crystallization Process ◽  
Amorphous Structure ◽  
Al Alloys ◽  
Heat Of Mixing ◽  
Ti Alloys ◽  
Different Temperatures ◽  
Thermal Curve

A series of Fe40Co40Zr8M2B10 (M=Nb, V, Cr, Ti, W, Al) alloys were prepared using melt-spinning. The thermal curve, structure and magnetic property of alloys are examined. Because of different negative heat of mixing between elements, only Fe40Co40Zr8M2B10 (M=Nb, V, Cr, Ti) alloys form amorphous structure. These amorphous alloys are annealed at different temperatures under vacuum conditions. The crystallization processes of four amorphous alloys are similar. In the primary stage of crystallization process, only α-Fe (Co) phase precipitates and Co element mainly distributes in the residual amorphous. For the four alloys after annealing at 550°C, there is a few differences in saturation magnetization (Ms) and coercivity (Hc) due to their different microstructures.

Crystallization processes and magnetic properties of Fe78Co2Zr8Nb2B10-xGex (x = 0, 1, 2, 3) amorphous alloys

2014 ◽  
Vol 28 (20) ◽  
pp. 1450160
Author(s):  
Z. Hua ◽  
B. Zuo ◽  
Y. M. Sun ◽  
X. N. Wang ◽  
L. R. Dong ◽  
...  
Keyword(s):  
Magnetic Property ◽  
Amorphous Alloys ◽  
Melt Spinning ◽  
Crystallization Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Initial Stage ◽  
Different Temperatures ◽  
Change Trend

Fe 78 Co 2 Zr 8 Nb 2B10-x Ge x (x = 0, 1, 2, 3) amorphous alloys were prepared by melt-spinning and annealed at different temperatures. The microstructures and magnetic property were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM), respectively. The crystallization processes of Fe 78 Co 2 Zr 8 Nb 2 B 10 amorphous alloy at different quenching rates are similar and complex. The α- Fe ( Co ) and α- Mn type phases are observed in their initial stage of crystallization process. Hc increases with increasing annealing temperature in general. Only α- Fe ( Co ) phase is observed in the initial stage of the crystallization processes of Fe 78 Co 2 Zr 8 Nb 2 B 10-x Ge x (x = 0, 1, 2, 3) alloys. The change trend of coercivity is complex compared with Ge -free samples. The magnetic property of Fe 78 Co 2 Zr 8 Nb 2 B 7 Ge 3 is better.

Thermal Stability of Rapidly Quenched TI-NI-AL Amorphous Alloys

1985 ◽  
Vol 58 ◽  
Author(s):  
K. Aoki ◽  
K. Hiraga ◽  
T. Masumoto
Keyword(s):  
Thermal Stability ◽  
Amorphous Phase ◽  
Amorphous Alloys ◽  
Melt Spinning ◽  
Composition Range ◽  
Amorphous Matrix ◽  
Al Alloys ◽  
The Other ◽  
Molten State ◽  
Thermal Stability Of

ABSTRACTTi-Ni-Al alloys were rapidly quenched from a molten state by the melt spinning method. Three kinds of metastable phases, namely, amorphous,nonequilibrium and quasicrystalline phases are formed in these alloys. The amorphous phase is formed in the range of 35 to 70 at% Ti and 0 to 25 at% Al. The nonequilibrium phases are formed in the composition range of 25 to 33 at% Ti. On the other hand, fine quasicrystalline phases are distributed in the amorphous matrix of the Ti-rich alloys. Crystallization temperatures and the hardness of the amorphous alloys were also examined.

Extended x-ray absorption fine structure study on amorphous Nd–Fe–B alloys

1998 ◽  
Vol 13 (8) ◽  
pp. 2132-2138 ◽  
Author(s):  
Hiroyuki Kageyama ◽  
Kohei Kadono ◽  
Kohei Fukumi ◽  
Tetsuji Saito ◽  
Toshiro Kuji
Keyword(s):  
Local Structure ◽  
Amorphous Alloys ◽  
Crystallization Process ◽  
Nearest Neighbor ◽  
Amorphous Structure ◽  
Neighbor Distance ◽  
X Ray ◽  
Melt Spun ◽  
Nearest Neighbor Distance ◽  
X Ray Absorption

The local structure and crystallization behavior of Nd15Fe77Bx (x = 2−14) melt-spun alloys were studied by Nd L3 extended x-ray absorption fine structure (EXAFS). The conventional x-ray powder diffractometry studies showed that the Nd–Fe–B melt-spun ribbons had the amorphous structure regardless of the boron content. EXAFS studies of the local structure around the Nd atom confirmed that the Nd–Fe–B melt-spun alloys had the amorphous structure and virtually the same nearest neighbor distance from the Nd atom. The amorphous alloys were heated by a differential scanning calorimetry in order to investigate the variation in the local structure during the crystallization process by EXAFS measurements. Although no appreciable difference was found in the nearest neighbor distance of the Nd atom between the amorphous alloys and the crystallized alloys, the small variation in the nearest neighbor distance during the crystallization process was detected by EXAFS measurements.

Effect of Crystallization on the Electrical Resistance and Structure of Amorphous Fe-Co-Cr-B-Si Alloys / Wpływ Krystalizacji Na Oporność Elektryczną I Strukturę Amorficznych Stopów Fe-Co-Cr-B-Si

2012 ◽  
Vol 57 (4) ◽  
pp. 1031-1039
Author(s):  
H. Solomon ◽  
N. Solomon
Keyword(s):  
Electrical Resistivity ◽  
Electrical Properties ◽  
Amorphous Alloys ◽  
Melt Spinning ◽  
Amorphous Structure ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Investigation Methods ◽  
Melt Spinning Technique

The goal of this paper is to present the influence of temperature variation and iron substitution with Co on the structure and electrical properties of amorphous Fe75-xCoxCr1B7Si17 alloys (where x=1, 4, 7, and 10 at.%), obtained by melt-spinning technique. The electrical resistivity of the samples was measured by using a usual four-probe method from -160°C to 750°C. The electrical resistivity was also measured at room temperature for the amorphous Fe75-xCoxCr1B7Si17 ribbons annealed at various temperatures for different holding time. The annealed samples were also investigated by Vickers microhardness test. The amorphous structure of tested materials was examined by X-ray diffraction (XRD), Mossbauer spectroscopy, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) methods. Experimental results confirmed the utility of applied investigation methods and the influence of the Co content and annealing process on the crystallization, structure and electrical properties of examined amorphous alloys.

Crystallization process and magnetic property of Fe81Zr3Nb6B10 alloy

2015 ◽  
Vol 29 (31) ◽  
pp. 1550196 ◽  
Author(s):  
Y. M. Sun ◽  
W. Q. Yu ◽  
D. Long ◽  
Y. Zhang ◽  
Z. Hua
Keyword(s):  
Thermal Analysis ◽  
Solid Solution ◽  
Magnetic Property ◽  
Differential Thermal Analysis ◽  
Melt Spinning ◽  
Crystallization Process ◽  
Annealing Temperature ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray

[Formula: see text] amorphous alloy was prepared by melt-spinning and annealed at various temperatures. The thermal property, microstructure and magnetic property were investigated by differential thermal analysis (DTA), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). The crystallization process of [Formula: see text] alloy is as follow: Amorphous [Formula: see text] residual amorphous [Formula: see text]-[Formula: see text]-[Formula: see text]-[Formula: see text] solid solution. Coercivity [Formula: see text] of [Formula: see text] alloy changes complexly, which abruptly deteriorates at 843 K and then softens with increasing annealing temperature [Formula: see text].

Study on Corrosion Resistance of Several Fe-Based Amorphous Alloys

2014 ◽  
Vol 789 ◽  
pp. 633-637
Author(s):  
Xiu Juan Tian ◽  
Wan Fu Liu ◽  
Kun Xie
Keyword(s):  
Corrosion Resistance ◽  
Amorphous Alloys ◽  
Melt Spinning ◽  
Open Circuit ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Annealing Temperatures ◽  
Structure Changes ◽  
Before And After ◽  
Different Temperatures

Three ribbons were obtained by rapid solidification using the melt-spinning techniques, and annealed with different temperatures. The corrosion behavior of ribbons in 0.1mol/L NaCl solution and the effects of annealing temperatures on the corrosion resistance were studied by open circuit potential and polarization curve test. Phase structure changes of the ribbons before and after corrosion were analyzed by X-ray diffraction (XRD). The amorphous forming ability and crystallization temperature of materials were characterized by differential scanning calorimetry (DSC). The surface morphology and composition before and after corrosion were analyzed by scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The result showed that Fe90Si5.5B4.5and Fe91Si5.5B3.5had high corrosion resistance. Corrosion resistance of the three ribbons had increased along with the increase of annealing temperatures.

Initiation of the Explosive Crystallization Process in Amorphous Alloys of the Fe-Zr System by Pulse Laser Treatment

2019 ◽  
Vol 11 (2) ◽  
pp. 02004-1-02004-5
Author(s):  
T. L. Tsaregradskaya ◽  
◽  
Yu. A. Kunitskyi ◽  
О. О. Kаlenyk ◽  
I. V. Plyushchay ◽  
...  
Keyword(s):  
Laser Treatment ◽  
Pulse Laser ◽  
Amorphous Alloys ◽  
Crystallization Process ◽  
Explosive Crystallization

scholarly journals Analysis of the Crystallization Kinetics and Thermal Stability of the Amorphous Mg72Zn24Ca4 Alloy

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3583
Author(s):  
Bartosz Opitek ◽  
Janusz Lelito ◽  
Michał Szucki ◽  
Grzegorz Piwowarski ◽  
Łukasz Gondek ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Crystallization Kinetics ◽  
Crystallization Process ◽  
Isothermal Annealing ◽  
Amorphous Structure ◽  
Avrami Equation ◽  
Temperature Phase ◽  
Scanning Calorimetry ◽  
Human Body Temperature ◽  
End Times

The aim of this study was to analyze the crystallization of the Mg72Zn24Ca4 metallic glass alloy. The crystallization process of metallic glass Mg72Zn24Ca4 was investigated by means of the differential scanning calorimetry. The glass-forming ability and crystallization are both strongly dependent on the heating rate. The crystallization kinetics, during the isothermal annealing, were modelled by the Johnson–Mehl–Avrami equation. Avrami exponents were from 2.7 to 3.51, which indicates diffusion-controlled grain growth. Local exponents of the Johnson–Mehl–Avrami equation were also calculated. In addition, the Mg phase—being the isothermal crystallization product—was found, and the diagram of the time–temperature phase transformation was developed. This diagram enables the reading of the start and end times of the crystallization process, occurring in amorphous ribbons of the Mg72Zn24Ca4 alloy on the isothermal annealing temperature. The research showed high stability of the amorphous structure of Mg72Zn24Ca4 alloy at human body temperature.

Enhanced Hydrogen Storage Kinetics of Melt Spun Nanocrystalline and Amorphous Mg2Ni-Type Alloy by Substituting Ni with Co

2011 ◽  
Vol 399-401 ◽  
pp. 1419-1424
Author(s):  
Yang Huan Zhang ◽  
Guo Fang Zhang ◽  
Xia Li ◽  
Zhong Hui Hou ◽  
Yin Zhang ◽  
...  
Keyword(s):  
Melt Spinning ◽  
Cast Alloy ◽  
Nanocrystalline Structure ◽  
Amorphous Structure ◽  
High Rate ◽  
Desorption Kinetics ◽  
Type Alloy ◽  
Nanocrystalline And Amorphous ◽  
Rate Discharge ◽  
High Rate Discharge

The nanocrystalline and amorphous Mg2Ni1-xCox (x=0, 0.1, 0.2, 0.3, 0.4) alloys were prepared by melt-spinning technique. The structures of the alloys were studied by XRD, SEM and HRTEM. The hydrogen absorption and desorption kinetics and the high rate discharge ability (HRD) of the alloys were measured. The results show that the as-spun Co-free alloy holds a typical nanocrystalline structure, whereas the as-spun alloys containing Co display a nanocrystalline and amorphous structure, confirming that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. The substitution of Co for Ni evidently improves the hydriding and dehydriding kinetics and the HRD of the alloys. With an increase in the amount of Co substitution from 0 to 0.4, the HRD value rises from 52.9% to 60.3% for the as-cast alloy, and from 65.9% to 76.0% for the as-spun (30 m/s) alloy.

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