scholarly journals Microstructural Investigations of Rapidly Solidified Al-Co-Y Alloys

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
B. Avar ◽  
M. Gogebakan ◽  
M. Tarakci ◽  
Y. Gencer ◽  
S. Kerli
Keyword(s):  
Melt Spinning ◽  
Alloy System ◽  
Supercooled Liquid ◽  
Amorphous Structure ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Glass Forming ◽  
Rapidly Solidified

The alloys with different compositions in the Al-rich corner of the Al-Co-Y ternary system were prepared by conventional casting and further processed by melt-spinning technique. The microstructure and the thermal behavior of the alloys were analyzed by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and differential thermal analysis (DTA). It was found that only rapidly solidified Al85Co7Y8alloy exhibited the best glass forming ability (GFA) and a fully amorphous structure. Besides, Al85Co13Y2and Al85Co2Y13alloy ribbons were fully crystalline, whereas Al85Co10Y5and Al85Co5Y10alloy ribbons consisted of some crystalline phases within an amorphous matrix. The SEM results showed the same trend that the crystalline phase fraction decreases with the approaching into best glass former. From DSC results, only Al85Co7Y8amorphous alloy exhibited a glass transition temperature (Tg) at 569 K, and its supercooled liquid region (ΔTx=Tx−Tg) was found to be 17 K. Moreover, other calculated GFA parameters for this alloy system were also discussed.

The Effect of Iron and Oxygen Additions on the Properties of Zr-Al-Cu-Ni Bulk Metallic Glass Forming Alloys

1996 ◽  
Vol 455 ◽  
Author(s):  
J. Eckert ◽  
N. Mattern ◽  
M. Seidel ◽  
L. Schultz
Keyword(s):  
Glass Transition ◽  
Oxygen Content ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Coarse Grained ◽  
Liquid Region ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Glass Forming ◽  
Fe Content

ABSTRACTThe effect of iron and oxygen additions on the thermal stability of rapidly quenched amorphous Zr65Al7.5Cu17.5Ni10) was studied by x-ray diffraction and differential scanning calorimetry. With increasing Fe content the glass transition temperature Tg and the crystallization temperature Tx shift to higher temperatures. The increase is more significant for Tg than for Tx, resulting in a decrease of the supercooled liquid region with increasing Fe content. For oxygen additions Tx decreases with increasing oxygen content whereas Tg increases slightly, causing a decrease of the supercooled liquid region with increasing oxygen content. The results reveal that even minor iron or oxygen contaminations lead to drastic changes in the glass transition behavior and the crystallization mode. Large iron or oxygen contents lead to the formation of nanocrystalline microstructures instead of coarse-grained material.

Superplastic Deformation and Viscous Flow in an Zr-Based Metallic Glass at 410°C

1998 ◽  
Vol 554 ◽  
Author(s):  
T. G. Nieh ◽  
J. G. Wang ◽  
J. Wadsworth ◽  
T. Mukai ◽  
C. T. Liu
Keyword(s):  
Strain Rate ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Single Strain ◽  
Transmission Electron ◽  
Heat Treated ◽  
Different Temperatures

AbstractThe thermal properties of an amorphous alloy (composition in at.%: Zr-10Al-5Ti-17.9Cu-14.6Ni), and particularly the glass transition and crystallization temperature as a function of heating rate, were characterized using Differential Scanning Calorimetry (DSC). X-ray diffraction analyses and Transmission Electron Microscopy were also conducted on samples heat-treated at different temperatures for comparison with the DSC results. Superplasticity in the alloy was studied at 410°C, a temperature within the supercooled liquid region. Both single strain rate and strain rate cycling tests in tension were carried out to investigate the deformation behavior of the alloy in the supercooled liquid region. The experimental results indicated that the alloy did not behave like a Newtonian fluid.

scholarly journals Glass formation in a (Ti, Zr, Hf)–(Cu, Ni, Ag)–Al high-order alloy system by mechanical alloying

2003 ◽  
Vol 18 (9) ◽  
pp. 2141-2149 ◽  
Author(s):  
L. C. Zhang ◽  
Z. Q. Shen ◽  
J. Xu
Keyword(s):  
Glass Transition ◽  
Mechanical Alloying ◽  
Glass Formation ◽  
Melt Spinning ◽  
Glassy Alloy ◽  
Alloy System ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
High Order ◽  
Liquid Region

In this work, glass formation under high-energy ball milling was investigated for a (Ti0.33Zr0.33Hf0.33)50(Ni0.33Cu0.33Ag0.33)40Al10 high-order alloy system with equiatomic substitution for early and late transition-metal contents. For comparison, an amorphous alloy ribbon with the same composition was prepared using the melt-spinning method as well. Structural features of the samples were characterized using x-ray diffraction, transmission electron microscopy, and differential scanning calorimetry. Mechanical alloying resulted in a glassy alloy similar to that obtained by melt spinning. However, the glass formation was incomplete, and a small amount of unreacted crystallites smaller than 30 nm in size still remained in the final ball-milled product. Like the melt-spun glass, the ball-milled glassy alloy also exhibited a distinct glass transition and a wide supercooled liquid region of about 80 K. Crystallization of this high-order glassy alloy proceeded through two main stages. After the primary nanocrystallization was completed, the remaining amorphous phase also behaved as a glass, showing a detectable glass transition and a large supercooled liquid region of about 100 K.

GLASS FORMING ABILITY AND KINETIC CHARACTERS OF PARAMAGNETIC Nd60Co40-xAlx(x=5, 10, 15) BULK METALLIC GLASSES

2004 ◽  
Vol 18 (14) ◽  
pp. 679-685 ◽  
Author(s):  
L. XIA ◽  
Y. D. DONG
Keyword(s):  
Glass Transition ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Glass Forming Ability ◽  
Ternary Alloys ◽  
Liquid Region ◽  
Scanning Calorimetry ◽  
Glass Forming

Paramagnetic Nd 60 Co 40-x Al x(x=5, 10, 15) bulk metallic glasses (BMGs) were prepared in the shape of rods 2 mm in diameter by suction casting. The ternary alloys have shown distinct glass transitions in Differential Scanning Calorimetry (DSC) measurements and excellent glass-forming ability. The glass transition and crystallization behaviors as well as their kinetics have been studied. The reduced glass transition temperature and the supercooled liquid region of the alloys were found to increase with the increasing content of Al . The role of Al was discussed. The parameter γ defined by Liu et al. was employed to discuss the glass-forming ability of the alloys and the critical cooling rates as well as the critical section thickness of the alloys were predicted accordingly.

scholarly journals Low-Temperature Annealing Induced Amorphization in Nanocrystalline NiW Alloy Films

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Z. Q. Chen ◽  
F. Wang ◽  
P. Huang ◽  
T. J. Lu ◽  
K. W. Xu
Keyword(s):  
Low Temperature ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
Alloy Films ◽  
Glass Forming ◽  
Low Temperature Annealing ◽  
Transmission Electron

Annealing induced amorphization in sputtered glass-forming thin films was generally observed in the supercooled liquid region. Based on X-ray diffraction and transmission electron microscope (TEM) analysis, however, here, we demonstrate that nearly full amorphization could occur in nanocrystalline (NC) sputtered NiW alloy films annealed at relatively low temperature. Whilst the supersaturation of W content caused by the formation of Ni4W phase played a crucial role in the amorphization process of NiW alloy films annealed at 473 K for 30 min, nearly full amorphization occurred upon further annealing of the film for 60 min. The redistribution of free volume from amorphous regions into crystalline regions was proposed as the possible mechanism underlying the nearly full amorphization observed in NiW alloys.

Glass Forming Ability in Amorphous Ti50Cu35-xNi15Snx Alloys Prepared by Mechanical Alloying

2005 ◽  
Vol 475-479 ◽  
pp. 3451-3458 ◽  
Author(s):  
Chung Kwei Lin ◽  
C.C. Hsu ◽  
R.R. Jeng ◽  
Y.L. Lin ◽  
C.H. Yeh ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Differential Scanning Calorimeter ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Forming ◽  
Amorphous Powders ◽  
X Ray Absorption

in the present study, amorphous ti50cu35-xni15snx (x=0~7) alloy powders were synthesized by mechanical alloying technique. the amorphization behavior of ti50cu28ni15sn7 alloy powders was examined in details by scanning electron microscopy, differential scanning calorimeter, x-ray diffraction, and synchrotron x-ray absorption spectroscopy. the results show that fully amorphous powders formed after 7 hours of milling. The thermal stability of the Ti50Cu35-xNi15Snx amorphous powders was investigated by differential scanning calorimeter. The amorphous Ti50Cu35Ni15 powders (i.e., x=0) exhibit no glass transition behavior. However, the amorphous Ti50Cu35-xNi15Snx (x=3~7) powders were found to exhibit a supercooled liquid region before crystallization. Amorphous Ti50Cu28Ni15Sn7 alloy powders exhibits a wide supercooled liquid region of 61 K.

Structure of the Amorphous-Crystalline Fe66Cu6B19Si5Nb4 Alloy Obtained by the Melt-Spinning Process

2013 ◽  
Vol 58 (2) ◽  
pp. 601-605 ◽  
Author(s):  
T. Kozieł ◽  
J. Latuch ◽  
A. Zielińska-Lipiec
Keyword(s):  
Melt Spinning ◽  
Amorphous Matrix ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Heat Of Mixing ◽  
Liquid Region ◽  
X Ray Diffraction ◽  
Spinning Process ◽  
Diffraction Patterns ◽  
Structure Investigations

This paper presents structure investigations of the rapidly cooled Fe66Cu6B19Si5Nb4 alloy. A proper selection of chemical composition enabled in-situ formation of the amorphous-crystalline composite during the melt spinning process. Liquid phase separation into the Fe-rich and the Cu-rich phases was confirmed. The microstructures of alloy, melt-spun from 1723 and 1773 K, are composed of the Fe-rich amorphous matrix and Cu-rich spherical crystalline precipitates. For the higher melt-ejection temperature, no coarse precipitates could be observed. Amorphous nature of the Fe-rich matrix was confirmed by presence of a broad diffraction maximum on the X-ray diffraction patterns, a halo ring on the electron diffraction pattern as well as presence of exothermic effects, related to the crystallization of the Fe-rich amorphous matrix, in the differential scanning calorymetry. Beside presence of copper, revealing positive heat of mixing with iron, relatively large supercooled liquid region, was noticed.

scholarly journals The Influence of Annealing Temperature on Microstructure and Magnetic Properties of Fe74Co3Si8B10Al1Nb4 Amorphous Alloy Ribbons

2017 ◽  
Vol 2 (1) ◽  
pp. 44-47
Author(s):  
Shih Fan Chen ◽  
Chih Yuan Chen ◽  
Chien Fan Chiang
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloy ◽  
Coercive Force ◽  
Saturation Magnetization ◽  
Melt Spinning ◽  
Annealing Temperature ◽  
Supercooled Liquid ◽  
Amorphous Structure ◽  
X Ray Diffraction ◽  
Scanning Calorimetry

Multi-component alloy ribbons with a composition of Fe74Co3Si8B10Al1Nb4 were prepared by a single roller melt-spinning method. The alloy had a fully amorphous structure, as determined by X-ray diffraction. The alloy ribbons were annealed for 10 min at temperatures of 350, 400, 450, 500, 550 and 600 oC, respectively. Differential scanning calorimetry curves indicated that the glass transition temperature (Tg) and the supercooled liquid range (ΔTx) of the amorphous alloy ribbon were about 494 oC and 43 oC, respectively. The ribbons showed soft magnetic properties, with a Curie temperature (Tc) at 284 oC, high saturation magnetization (Ms) of 1.18 T, and coercive force (Hc) of 33.66 A/m. In the present study, both saturation magnetization and coercive force of amorphous alloy ribbons increased with increasing the annealing temperature, due to precipitations and growth of α–Fe phase nanocrystals in the amorphous matrix. On the other hand, it was found that the coercive force of alloy ribbons reduced as a consequence of precipitations of Nb3Si phase if the annealing temperature reached 600 oC.

Effect of Cu and Gd on Structural and Magnetic Properties of Fe-Co-B-Si-Nb Metallic Glasses

2016 ◽  
Vol 254 ◽  
pp. 60-64 ◽  
Author(s):  
Parthiban Ramasamy ◽  
Mihai Stoica ◽  
Mariana Calin ◽  
Jurgen Eckert
Keyword(s):  
Magnetic Properties ◽  
Crystallization Behavior ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Glass Forming Ability ◽  
Liquid Region ◽  
Scanning Calorimetry ◽  
Glass Forming ◽  
Mold Casting ◽  
Different Diameters

[(Fe0.5Co0.5)0.75B0.2Si0.05]96Nb4}100-x,y(Gdx, Cuy) (x = 0.5, 1 and 2), (y = 0.5) alloys with different diameters were prepared by copper mold casting. The structure, the thermal and the magnetic properties were studied by X-ray diffraction, differential scanning calorimetry and vibrating sample magnetometry, respectively. Minor Cu addition completely changes the crystallization behavior, and also the glass-forming ability decreases because of the decrease in the supercooled liquid region. However, the magnetic properties are significantly improved upon annealing because of the precipitation of (Fe,Co) phase. In case of [(Fe0.5Co0.5)0.75B0.2Si0.05]96Nb4}100-x (Gdx) glass, Gd addition does not change the crystallization behavior. In turn, it increases the supercooled liquid region when compared with [(Fe0.5Co0.5)0.75B0.2Si0.05]96Nb4, but even then the glass-forming ability is reduced (critical glassy diameter dc < 1.5 mm). The saturation magnetization of the glass is also decreased with increasing Gd content.

PREPARATION AND STRUCTURAL STUDY OF MECHANICAL ALLOYED OF Co50Fe20Cu2V8B20

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2775-2779
Author(s):  
X. F. ZHANG ◽  
X. Q. HUANG ◽  
R. W. PENG ◽  
G. Q. WANG ◽  
S. Y. ZHANG
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Amorphous Alloys ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron

The amorphous alloys of Co 50 Fe 20 Cu 2 V 8 B 20 are successfully obtained by using the mechanical alloying technique. The sample is analyzed by X-ray diffraction, transmission electron microscopy and differential scanning calorimetry. The DSC result of the powder sample milled for 120 h shows a complete amorphous phase and a wide supercooled liquid region (Tx - Tg ≃ 80 K ).

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