Glass Forming Ability and Thermal Properties of a Cu-Based Bulk Metallic Glass Microalloyed with Silicon

2007 ◽  
Vol 561-565 ◽  
pp. 1341-1344 ◽  
Author(s):  
Jason S.C. Jang ◽  
Y.C. Huang ◽  
C.H. Lee ◽  
I.S. Lee ◽  
L.J. Chang

The (Cu42Zr42Al8Ag8)100-xSix amorphous alloy rods, x =0 to 1, with 3 mm in diameter were prepared by Cu-mold drop casting method. The glass forming ability, thermal properties and microstructure evolution was studied by differential scanning calorimetry (DSC), and X-ray diffractometry (XRD). The XRD result reveals that these as-quenched (Cu42Zr42Al8Ag8)100-xSix alloy rods exhibit a broaden diffraction pattern of amorphous phase. The crystallization temperature and GFA (glass forming ability) of (Cu42Zr42Al8Ag8)100-xSix alloys increase with the silicon additions. The highest Trg (0.59) and γ value (0.405) occurred at the (Cu42Zr42Al8Ag8)99.75Si0.25 and (Cu42Zr42Al8Ag8)99.5Si0.5 alloy. In addition, both of the activation energy of crystallization and the incubation time of isothermal annealing for these (Cu42Zr42Al8Ag8)100-xSix alloys indicates that the (Cu42Zr42Al8Ag8)99.25Si0.75 alloy posses the best thermal stability among the (Cu42Zr42Al8Ag8)100-xSix alloy system.

2007 ◽  
Vol 22 (2) ◽  
pp. 453-459 ◽  
Author(s):  
Z.W. Zhu ◽  
H.F. Zhang ◽  
W.S. Sun ◽  
Z.Q. Hu

The effect of zirconium (Zr) addition on the glass-forming ability (GFA) and mechanical properties of the Ni61.5Nb38.5 alloy has been studied. The addition of Zr improves the GFA. When x = 5 for Ni61.5Nb38.5−xZrx (in at.%) alloys, the alloy exhibits the best GFA and can be cast into 3-mm-diameter amorphous samples by using the copper mold injection-casting method. Differential scanning calorimetry measurements indicated that the thermal parameters, such as Trg and γ, have not a good correlation with the GFA in the Ni–Nb–Zr alloys. Compression tests reveal that the addition of Zr just decreases the fracture strength slightly from 3.4 to 3 GPa and that all of the tested samples exhibit a little compressive plasticity of about 2%. When x = 9, the feature of the fracture surface indicates that the alloy has a tendency for transition from the ductile to the brittle. And delicate “dimple” and microscale vein pattern structures have been observed on it.


2003 ◽  
Vol 18 (7) ◽  
pp. 1588-1593
Author(s):  
Yi Lei ◽  
M. Calvo-Dahlborg ◽  
J.M. Dubois ◽  
Zukun Hei ◽  
P. Weisbecker ◽  
...  

A pseudoternary alloy system was constructed by combining icosahedral quasicrystal (IQC), decagonal quasicrystal (DQC), and Zr into one alloy system. Different proportions of Zr were added into pseudobinary alloy IQC80DQC20 (in wt.%). The structural evolution in these alloys is discussed. An amorphous alloy composition was found in this system. Melt-spinning amorphous alloy was produced in this composition. Through differential scanning calorimetry experiments, the amorphous alloy exhibited a high glass-forming ability comparable to that of the Inoue alloy Zr65Al7.5Cu17.5Ni10.


2005 ◽  
Vol 475-479 ◽  
pp. 3393-3396
Author(s):  
Hui Xu ◽  
Xiao Hua Tan ◽  
Nannan Qi ◽  
Qing Wang ◽  
Yuanda Dong

The glass-forming ability, thermal stability and magnetic properties of the Nd60-xDyxFe30Al10 (x=0, 2, 5) bulk amorphous alloys were investigated by x-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscope (SEM) and the vibrating sample magnetometer (VSM). The results show that the glass forming ability of the Nd60-xDyxFe30Al10 (x=0, 2, 5) alloys decrease with increasing Dy content. The as-cast Nd60-xDyxFe30Al10 (x=0, 2, 5) alloys show hard magnetic behavior at room temperature. With increasing Dy content, the intrinsic coercivity of the alloys increase significantly while the saturation magnetization and remanence of the alloys decrease monotonously. With increasing annealed temperature, the intrinsic coercivity of the Nd55Fe30Al10Dy5 alloy decreased significantly, while the saturation magnetization and remanence decrease monotonously. The Nd55Fe30Al10Dy5 alloy shows soft magnetic behavior after annealed at 773K for 30 min.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Jiun-Yi Tseng ◽  
Yuan-Tsung Chen ◽  
Z. G. Chang ◽  
C. W. Wu ◽  
L. C. Yang

We examined two targets containing Co40Fe40B20and Co60Fe20B20. We deposited Co40Fe40B20and Co60Fe20B20monolayer thin films of various thicknesses on glass substrates through DC magnetron sputtering; the thicknesses ranged from 25 to 200 Å. The thermal properties of the Co40Fe40B20and Co60Fe20B20thin films were determined using a differential scanning calorimeter (DSC). The thermal properties included the glass transition temperature (Tg), onset crystallization temperature (Tx), and glass-forming ability, which were determined according to these values. Using the Kissinger formula revealed that the activation energy of the Co60Fe20B20with a thickness of 75 Å is the highest, implying that crystallization was the lowest and the Co60Fe20B20film showed anticrystallization properties. However, the energy of 75 Å Co40Fe40B20thin films was the lowest, which is opposite to that of Co60Fe20B20. This observation can be reasonably explained based on the concentration of Co or Fe. Therefore, a thickness of 75 Å is critical.


2012 ◽  
Vol 583 ◽  
pp. 82-85
Author(s):  
Yong Jun Tang ◽  
Hui Xu ◽  
Xiao Hua Tan ◽  
Hua Man ◽  
Qin Bai

Bulk Nd60-xCo15+xAl25 (where x =0, 2, 5, 8, 11) sheet alloys were prepared by argon arc melting and suction casting a copper mold. Glassing forming ability (GFA) of these alloys was investigated by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Due to the dissimilarity reflected from DSC curves the thermodynamic calculation was applied. The values of Gibbs free energy (∆Gl-x (Tg)) for the amorphous alloys were gave out and some GFA criterions were adopted to make a comparison among the samples.


2008 ◽  
Vol 01 (02) ◽  
pp. 145-149 ◽  
Author(s):  
JUNG MIN NAM ◽  
YONG HEE LEE ◽  
TAE HYUN NAM ◽  
YEON WOOK KIM ◽  
JUNG MOO LEE

Amorphous Ti 50 Ni (50-x) Cu x (at.%) (x = 15, 20 and 25) alloy ribbons were prepared by melt spinning, and then their crystallization behavior was investigated by optical microscopy, transmission electron microscopy, X-ray diffraction and differential scanning calorimetry. Wavenumber (Qp) decreased from 29.40 nm-1 to 29.29 nm-1 and ΔT(T g - T x ) increased from 31 K to 36 K with increasing Cu content from 15 at.% to 25 at.%, suggesting that glass forming ability of Ti – Ni – Cu alloy ribbons increased with increasing Cu content. Activation energy for crystallization decreased from 211.5 kJ/mol to 136.4 kJ/mol with increasing Cu content from 15 at.% to 25 at.%, suggesting that a stability of Ti – Ni – Cu amorphous decreased with increasing Cu content.


2000 ◽  
Vol 644 ◽  
Author(s):  
Nobuyuki Nishiyama ◽  
Mitsuhide Matsushita ◽  
Akihisa Inoue

AbstractGlass-forming ability, thermal stability and nucleation behavior of a Pd40Cu30Ni10P20 alloy prepared using a high purity polycrystalline phosphorus are investigated. The critical cooling rate for glass formation for the high purity alloy is the same as that for the previous result, but the improvement of undercooling reaches about 80 K as compared with the fluxed ordinary alloy. In comparison with the non-fluxed alloy, the solidified structure of the present highly purified alloy is significantly different. The non-fluxed sample shows the characteristic “island-like” structure consisted of acicular fcc-Pd2Ni2P solid solution and Cu3Pd intermetallic compound. These acicular phases appear to be caused by the growth of quenched-in nuclei. In the isothermal experiment, nucleus density exhibits time dependence even at 683 K near the nose temperature. It is assumed that the crystallization behavior for the highly purified alloy is closer to homogeneous nucleation from quenched-in nuclei dominant behavior. In order to investigate the nucleation behavior, in-situ TEM observation was carried out. Spherical Pd15P2 particle with a diameter about 15 nm is observed, and this spherical region repeats generation and annihilation during isothermal annealing. The reason for the high glass-forming ability is discussed on the basis of the obtained results.


2007 ◽  
Vol 22 (2) ◽  
pp. 471-477 ◽  
Author(s):  
Dong Ho Kim ◽  
Jin Man Park ◽  
Do Hyang Kim ◽  
Won Tae Kim

The effects of niobium (Nb) addition on the glass-forming ability (GFA), crystallization behavior, and compressive mechanical property of iron (Fe)–boron (B)–yttrium (Y) alloys have been investigated. Among the (Fe71.2B24Y4.8)100−xNbx (x = 0, 2, 4, 6, 8) alloys investigated, (Fe71.2B24Y4.8)96Nb4 exhibits the highest GFA, enabling the formation of glassy rods with a maximum diameter of 7 mm, which is the largest among quaternary Fe-based alloys. The comparison of the crystallization behavior of the alloys shows that the formation of metastable Fe23B6 phase during crystallization in the (Fe71.2B24Y4.8)96Nb4 alloy can suppress the formation of other stable crystalline phases such as α-Fe, enhancing the stability of the glass phase. The present results show that the attainment of a significantly high GFA is possible even in a quaternary Fe-based alloy system by properly tailoring the competing crystalline phase by the modification of liquid chemistry.


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