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.

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.

Critical Cooling Rate of Y36Nd20Al24Co20 Bulk Amorphous Alloy

2014 ◽  
Vol 670-671 ◽  
pp. 86-89
Author(s):  
Shi Wen He
Keyword(s):  
Glass Transition ◽  
Amorphous Alloy ◽  
Cooling Rate ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Glass Forming Ability ◽  
Bulk Amorphous Alloy ◽  
Liquid Region ◽  
Critical Cooling Rate ◽  
Glass Forming

A new bulk amorphous alloy, Y36Nd20Al24Co20, with a diameter of 5 mm was successfully fabricated by the method of equiatomic substitution for the Y element in Y56Al24Co20amorphous alloy. The values of the supercooled liquid region ∆Tx(=Tx-Tg), the reduced glass transition temperature Trg(=Tg/Tl) and the parameter γ (=Tx/(Tg+Tl)) for Y36Nd20Al24Co20bulk amorphous alloy are 60K, 0.605 and 0.415, respectively. The critical cooling rate of the Y36Nd20Al24Co20bulk amorphous alloy was determined to be 40 K/s, providing an indication that this alloy has a high glass-forming ability.

scholarly journals Combinatorial measurement of critical cooling rates in aluminum-base metallic glass forming alloys

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Naijia Liu ◽  
Tianxing Ma ◽  
Chaoqun Liao ◽  
Guannan Liu ◽  
Rodrigo Miguel Ojeda Mota ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Cooling Rate ◽  
Laser Heating ◽  
Glass Forming Ability ◽  
Rapid Screening ◽  
Composition Effect ◽  
Cooling Rates ◽  
Critical Cooling Rate ◽  
Glass Forming ◽  
Aluminum Base

AbstractDirect measurement of critical cooling rates has been challenging and only determined for a minute fraction of the reported metallic glass forming alloys. Here, we report a method that directly measures critical cooling rate of thin film metallic glass forming alloys in a combinatorial fashion. Based on a universal heating architecture using indirect laser heating and a microstructure analysis this method offers itself as a rapid screening technique to quantify glass forming ability. We use this method to identify glass forming alloys and study the composition effect on the critical cooling rate in the Al–Ni–Ge system where we identified Al51Ge35Ni14 as the best glass forming composition with a critical cooling rate of 104 K/s.

scholarly journals On Glass Forming Ability of Bulk Metallic Glasses by Relating the Internal Friction Peak Value

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 767
Author(s):  
Xianfeng Zhang ◽  
Xiao Cui ◽  
Zhuotong Du ◽  
Fangqiu Zu ◽  
Jinjing Li ◽  
...  
Keyword(s):  
Internal Friction ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Glass Forming Ability ◽  
Liquid Region ◽  
Internal Friction Peak ◽  
Glass Forming ◽  
Constituent Elements ◽  
Valid Criterion ◽  
Peak Value

The internal friction (IF) behaviors of a series of LaCe-, Zr-, and La-based bulk metallic glasses (BMGs) were studied by a computer-controlled, conventional inverted torsion pendulum. The results indicate that with an increasing temperature, the IF also increases gradually in the supercooled liquid region, followed by a decrease caused by crystallization. BMGs with a good glass forming ability (GFA) usually possess a high IF peak value for an alloy system with the same constituent elements. Furthermore, the magnitude of the IF value (Qi−1) of the inflection point is an efficient criterion of GFA. The Qi−1 value is a valid criterion under the conditions of identical constituent elements and different element contents. However, Qi−1 and GFA have no relationship among different alloy systems.

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.

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