Discussion on Relationship between Viscosities of Molten Zr-Cu Based Alloys and their Glass Forming Ability

2011 ◽  
Vol 194-196 ◽  
pp. 1242-1246
Author(s):  
Jing Song Wang ◽  
Li Jun Cao ◽  
Jing Hua Wang ◽  
Hao Yan Sun ◽  
Shu You Huang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Rotating Cylinder ◽  
Glass Forming Ability ◽  
Vacuum Condition ◽  
Glass Forming ◽  
Amorphous Sample ◽  
Cylinder Method ◽  
The Relationship

The dynamic viscosities of molten Zr55Ni5Al10Cu30 and Zr50Cu50 alloys were measured by using rotating cylinder method under non-vacuum condition. According to the lnη~1/T curves, discontinuous changes were found and the activation energy was calculated. The activation energy of molten Zr55Ni5Al10Cu30 alloy is obviously larger than that of molten Zr50Cu50 alloy. Amorphous sample of Zr55Ni5Al10Cu30 with 3mm diameter was prepared successfully under non-vacuum condition, but there are crystallization phases in Zr50Cu50 amorphous sample with 2mm diameter. The relationship between viscosities of molten Zr-Cu based alloys and their glass forming ability (GFA) was discussed, and viscosities of molten Zr-Cu based alloys play an important role on their GFA.

Investigation on Correlation between the Modified Criterion and the Glass-Forming Ability for Metallic Glasses

2010 ◽  
Vol 97-101 ◽  
pp. 591-596
Author(s):  
Wen Bin Sheng ◽  
Chun Ming Zhang ◽  
Wan Li Gu
Keyword(s):  
Aqueous Solutions ◽  
Cooling Rate ◽  
Metallic Glasses ◽  
Statistical Correlation ◽  
Glass Forming Ability ◽  
Correlation Parameter ◽  
Glass Forming ◽  
A Value ◽  
The Relationship ◽  
Modified Equation

A modified criterion γ’ (=Tx/(1.5Tg+Tl) of glass-forming ability (GFA) for metallic glasses is suggested on the basis of present criterion γ (=Tx/(Tg+Tl) that correlates well with some systems including metallic glasses, some glassy oxides and some cryo-protective aqueous solutions. Results show that the modified criterion γ’ shows stronger correlation with the critical cooling rate Rc for metallic glasses than the criterion γ, which is demonstrated by a value increase in the statistical correlation parameter R2 from 0.9022 to 0.9037. Furthermore, a modified equation is given to reflect the relationship between γ’ and Rc.

Effects of basicity and CaF2 on the viscosity of CaF2–CaO–SiO2 slag for electroslag remelting process

2019 ◽  
Vol 116 (6) ◽  
pp. 638 ◽  
Author(s):  
Yigui Lao ◽  
Yunming Gao ◽  
Fangjie Deng ◽  
Qiang Wang ◽  
Guangqiang Li
Keyword(s):  
Rotating Cylinder ◽  
Electroslag Remelting ◽  
Experimental Conditions ◽  
Ft Ir ◽  
Cylinder Method ◽  
The Fourier Transform ◽  
The Relationship ◽  
Complex Anions ◽  
Silicate Complex ◽  
Ft Ir Spectroscopy

Effects of the basicity and the CaF2 content on viscosity of CaF2–CaO–SiO2 slag with high CaF2 content for electroslag remelting process were investigated by the rotating cylinder method in the temperature ranging from 1773 to 1533 K. The relationship between the structure and the viscosity variation of the slag was also clarified by the Fourier transform infrared (FT-IR) spectroscopy of water-quenched slags. The results show that the viscosity gradually decreases with the increase in the basicity of the slag from 1 to 3 under the present experimental conditions. It is found that the CaO does not depolymerize all silicate complex anions for the slag with the basicity of 1 at 1773 K and there are still some bridging oxygens. With the increase in the basicity to 3, the silicate complex anions are almost completely depolymerized to simple ions. As the CaF2 content increases from 40 to 80 mass%, the viscosity of the slag decreases due to the dilution of CaF2 for the concentration of the silicate complex anions in unit volume of the slag. Moreover, the effect of the temperature on the viscosity is not remarkable. The activation energy of viscous flow exhibits the decrease from 40.4 to 26.7 kJ · mol−1 with the increase in the basicity from 1 to 3, and also the decrease from 66.6 to 31.0 kJ · mol−1 with the increase in the CaF2 content from 40 to 80 mass%.

Melt Temperature Dependence on Glass Forming Ability of Al-Mg Alloys

2009 ◽  
Vol 79-82 ◽  
pp. 191-194
Author(s):  
Hao Ran Geng ◽  
Yan Bo Deng ◽  
Zhi Ming Wang ◽  
Xue Liang Wang ◽  
Zhen Yuan Li
Keyword(s):  
Melt Spinning ◽  
Liquid Structure ◽  
Glass Forming Ability ◽  
Dsc Analysis ◽  
X Ray Diffraction ◽  
Melt Temperature ◽  
X Ray ◽  
Glass Forming ◽  
The Relationship ◽  
Al Mg Alloys

The relationship between the viscosity of Al84Mg10Ce6 alloy melt and liquid structure was studied by viscosity measurements, X-ray diffraction and DSC analysis in this paper. In addition, the glass forming ability of alloy ties produced by melt spinning was analyzed. Based on the above results, the relationship between alloy melts and its glass forming ability(GFA)was studied. The addition of element Ce leads to the abnormal change of Al84Mg10Ce6 melt’ s structure and enhances its GFA, furthermore, it results in completely amorphous ties with melt spinning at 850°C.Therefore, there is certain relationship between the Al-Mg based alloys melt and its GFA.

Thermal conductivity of metallic glassy alloys and its relationship to the glass forming ability and the observed cooling rates

2008 ◽  
Vol 23 (8) ◽  
pp. 2283-2287 ◽  
Author(s):  
Dmitri V. Louzguine-Luzgin ◽  
Takanobu Saito ◽  
Junji Saida ◽  
Akihisa Inoue
Keyword(s):  
Thermal Conductivity ◽  
Glassy Alloy ◽  
Glass Forming Ability ◽  
Bulk Glass ◽  
Cooling Rates ◽  
Glass Forming ◽  
Glassy Alloys ◽  
Mold Casting ◽  
Cooling Behavior ◽  
The Relationship

In this work, we study the cooling behavior of several typical bulk glassy alloys on casing and present the relationship between the thermal conductivity of a glassy alloy and the cooling rate upon mold casting. The cooling rates obtained for Ti-, Zr-, Pd-, and Cu-based bulk glass forming alloys are found to scale with the thermal conductivities of the studied glassy alloys.

Influence of Nb2O5 and basicity on the viscosity and structure of CaO-SiO2-Nb2O5-CeO2-CaF2 slag system

2020 ◽  
Vol 117 (3) ◽  
pp. 307
Author(s):  
Zhuang Ma ◽  
Zengwu Zhao ◽  
Wentao Guo ◽  
Zhi Wang
Keyword(s):  
Activation Energy ◽  
Slag System ◽  
Rotating Cylinder ◽  
Degree Of Polymerization ◽  
X Ray Diffraction ◽  
Structural Units ◽  
X Ray ◽  
Reducing Atmosphere ◽  
Bayan Obo ◽  
Cylinder Method

In order to utilize niobium concentrate of Bayan Obo effectively, the effect of Nb2O5 and basicity on the viscosity of CaO-SiO2-Nb2O5-5.0 wt.% CeO2-5.0 wt.% CaF2 slag system was studied from 1653 to 1813 K in reducing atmosphere by rotating cylinder method. For the same condition, the as-quenched samples were investigated through X-ray diffraction and Raman spectroscopy. The results show that the viscosity, break temperature and activation energy of viscous flow decrease with the increase of Nb2O5 and basicity. Raman spectra show that the Nb4+ ions exist in the form of [NbO6] octahedron with different distortion and little [NbO4] tetrahedron in the slags. The Nb2O5 addition and basicity lower the degree of polymerization, where the complex Si-O network is depolymerized into simple structural units.

Quantitative Evaluation of the Glass Forming Ability of (Cu-Zr) Based Glass Alloys with Thermodynamics Method

2011 ◽  
Vol 239-242 ◽  
pp. 1622-1625
Author(s):  
Hui Qiang Li ◽  
Long Fei Liu
Keyword(s):  
Cooling Rate ◽  
Nucleation Rate ◽  
Glass Forming Ability ◽  
Crystalline Fraction ◽  
Critical Cooling Rate ◽  
Glass Forming ◽  
Element Number ◽  
The Relationship ◽  
Peak Value ◽  
Crystalline Growth

Along nucleation → crystalline growth →crystalline fraction → critical cooling rate, the relationship between the nucleation, elements, cooling rate and the Glass Forming Ability of (Cu-Zr) based glass alloys is quantitatively studied with thermodynamics method, and a better method to evaluate the critical cooling rate of glass alloys is also proposed in this paper. The computed results show that: (1) with the increase of element number, the steady state nucleation rate drops gradually. From Cu-Zr, Cu-Zr-Al, Cu-Zr-Al-Ni, to Cu-Zr-Al-Ni-Ti, the peak value of nucleation rate decreases from 1021mol-1s-1to 1013mol-1s-1. It is also found the nucleation rate both drops with the substitution of Ni with Cu or Al with Zr; (2) with the increase of cooling rate, the nucleation rate drops sharply. When the cooling rate reaches 103K/s, the nucleation rates of Cu64Zr36, Cu54Zr42.5Al3.5, Cu55Zr40Al5and Cu30Zr55Al10Ni5drop to 109mol-1s-1, 106mol-1s-1, 107mol-1s-1and 103mol-1s-1accordingly.

Critical Cooling Rate and Thermal Stability in Zr-Ti-Cu-Ni-Be Bulk Metallic Glasses

2000 ◽  
Vol 644 ◽  
Author(s):  
Theodore A. Waniuk ◽  
Jan Schroers ◽  
William L. Johnson
Keyword(s):  
Thermal Stability ◽  
Cooling Rate ◽  
Metallic Glasses ◽  
Glass Forming Ability ◽  
Liquid Region ◽  
Continuous Increase ◽  
Critical Cooling Rate ◽  
Glass Forming ◽  
The Relationship ◽  
Tie Line

AbstractThe crystallization behavior of a series of alloys in the Zr-Ti-Cu-Ni-Be system is studied. Upon cooling from the molten state with different rates, alloys with compositions ranging along a tie line from (Zr75Ti25)55(Ni45Cu55)22.5Be22.5 (Vit1) to (Zr85Ti15)55(Ni57Cu43)17.5Be27.5 (Vit4) show a continuous increase in the critical cooling rate to suppress crystallization. In contrast, thermal analysis of the same alloys shows that the undercooled liquid region, the temperature difference between the glass transition temperature and the crystallization temperature, is largest for compositions midway between the two endpoints, revealing that glass forming ability does not correlate with thermal stability. The relationship between the change in glass forming ability and thermal stability is discussed with reference to a chemical decomposition process.

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