Thermal glass transition beyond kinetics of a non-crystallizable glass-former

Soft Matter ◽  
2018 ◽  
Vol 14 (18) ◽  
pp. 3601-3611 ◽  
Author(s):  
Martine Philipp ◽  
Christophe Nies ◽  
Martin Ostermeyer ◽  
Wulff Possart ◽  
Jan K. Krüger
Keyword(s):  
Thermal Expansion ◽  
Glass Transition ◽  
Glass Forming ◽  
Thermodynamics And Dynamics ◽  
Kinetics Of

Simultaneous access to thermodynamics and dynamics of glass-forming poly(vinylacetate) via static and dynamic thermal expansion.

Kinetics of Glass Formation by Solidification and Melting

1990 ◽  
Vol 205 ◽  
Author(s):  
Hans J. Fecht
Keyword(s):  
Glass Transition ◽  
Specific Heat ◽  
Glass Formation ◽  
Excess Entropy ◽  
Crystalline Solid ◽  
Thermally Activated ◽  
Glass Forming ◽  
Local Fluctuations ◽  
Measured Specific Heat ◽  
Kinetics Of

AbstractA scenario has been developed combining the glass transition (liquid to glass) with the crystal-to glass transition. If the “melting” point of a crystalline solid solution is reduced to the ideal glass transition temperature a triple point is predicted between crystal, liquid and glass. Based on extrapolations of measured specific heat data of undercooled liquid glass-forming Au- Pb-Sb alloys the excess entropy is found to vanish close to the glass transition. On the other hand, the amorphization reaction of crystalline Fe2Er-hydrides is characterized by a lambda-type anomaly in the specific heat. The logarithmic temperature-dependence of the specific heat results from local fluctuations in the crystalline phase, rather than thermally activated lattice defects. These results suggest that glass formation from the liquid as well as the crystalline state is characterized by an underlying instability.

STUDY OF GLASS TRANSITION KINETICS FOR Co66Si12B16Fe4Mo2 METALLIC GLASS

2013 ◽  
Vol 22 ◽  
pp. 321-326 ◽  
Author(s):  
ASHMI T. PATEL ◽  
ARUN PRATAP
Keyword(s):  
Glass Transition ◽  
Metallic Glass ◽  
Glass Forming Ability ◽  
Fragility Index ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Glass Transition Kinetics ◽  
Glass Forming ◽  
The Given ◽  
Kinetics Of

Metallic glasses have received considerable attention in comparison to normal metallic materials due to their superior physical, mechanical, electrical and magnetic properties. Understanding the glass transition kinetics of metallic alloys is of great importance in order to know its thermal stability. In the present paper, kinetics of glass transition of metallic glass Co66Si12B16Fe4Mo2 is studied using thermal analysis technique, i.e. differential scanning calorimetry (DSC), by non-isothermal heating of the sample at four different heating rates. The activation energy (E) of the glass transition region is determined by two most frequently used methods, namely, Moynihan’s method and Kissinger’s equation. The fragility index, m is also calculated using Tg, which is a measure of glass forming ability of the given system. The results show that the fragility index ‘m’ of the given system falls below 16. This clearly indicates that the given system is strong liquid with excellent glass forming ability (GFA).

On the crystallization kinetics of Zr–(Co,Ni)–Al bulk metallic glasses

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744012 ◽  
Author(s):  
X. M. Qin ◽  
Q. F. Zhang ◽  
X. Y. Duan ◽  
X. C. Wang ◽  
Y. H. Jiang ◽  
...  
Keyword(s):  
Glass Transition ◽  
Crystallization Kinetics ◽  
Metallic Glasses ◽  
Amorphous Alloys ◽  
Low Cost ◽  
Glass Forming ◽  
Characteristic Temperatures ◽  
Crystallization Ability ◽  
Higher Temperature ◽  
Kinetics Of

Zr-based amorphous alloys are promising materials applied in engineering field, due to their strong glass-forming ability, outstanding mechanical properties and relatively low cost. In this work, the crystallization kinetics of Zr[Formula: see text]Co[Formula: see text]Ni[Formula: see text]Al[Formula: see text] ([Formula: see text], 2, 4 and 8; marked as Ni0, Ni2, Ni4 and Ni8, respectively) alloys are investigated in detail. The results show that, due to the addition of Ni, the glass transition of the alloys presents obvious dynamic characteristics, i.e., with the increasing heating rate, all characteristic temperatures are shifted to higher temperature. By fitting the Kissinger equation, the glass transition activation energy of Ni8 is the highest, indicating that Ni8 is much more difficult to crystallize. Therefore, the Ni8 alloy has the strongest anti-crystallization ability in the Zr[Formula: see text]Co[Formula: see text]Ni[Formula: see text]Al[Formula: see text] alloys investigated.

scholarly journals Physical Aging Behavior of a Glassy Polyether

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 954
Author(s):  
Xavier Monnier ◽  
Sara Marina ◽  
Xabier Lopez de Pariza ◽  
Haritz Sardón ◽  
Jaime Martin ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Physical Aging ◽  
Glassy State ◽  
Aging Behavior ◽  
Scanning Calorimetry ◽  
Narrow Temperature Range ◽  
Glass Forming ◽  
Fast Scanning Calorimetry

The present work aims to provide insights on recent findings indicating the presence of multiple equilibration mechanisms in physical aging of glasses. To this aim, we have investigated a glass forming polyether, poly(1-4 cyclohexane di-methanol) (PCDM), by following the evolution of the enthalpic state during physical aging by fast scanning calorimetry (FSC). The main results of our study indicate that physical aging persists at temperatures way below the glass transition temperature and, in a narrow temperature range, is characterized by a two steps evolution of the enthalpic state. Altogether, our results indicate that the simple old-standing view of physical aging as triggered by the α relaxation does not hold true when aging is carried out deep in the glassy state.

Glass Formation and Glass Forming Ability of Alloys Near Eutectic Composition

2000 ◽  
Vol 644 ◽  
Author(s):  
Y. Li
Keyword(s):  
Glass Transition ◽  
Glass Formation ◽  
Eutectic Composition ◽  
Glass Forming Ability ◽  
Critical Section ◽  
Bulk Glass ◽  
Melting Behaviour ◽  
Eutectic Alloys ◽  
Section Thickness ◽  
Glass Forming

AbstractOnset temperature, Tm and offset temperature (liquidus) Tl of melting of a series of bulk glass forming alloys based on La, Mg, and Pd have been measured by studying systematically the melting behaviour of these alloys using DTA or DSC. Bulk metallic glass formation has been found to be most effective at or near their eutectic points and less effective for off-eutectic alloys. Reduced glass transition temperature Trg given by Tg/Tl is found to show a stronger correlation with critical cooling rate or critical section thickness for glass formation than Trg given by Tg/Tm.

Applicability of Iron Phosphate Glass Medium for Loading NaCl Originated From Seawater Used for Cooling the Stricken Power Reactors

2013 ◽  
Author(s):  
Hidekazu Kobayashi ◽  
Ippei Amamoto ◽  
Takuma Yokozawa ◽  
Teruo Yamashita ◽  
Takayuki Nagai ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Glass Transition ◽  
Phosphate Glass ◽  
Glass Formation ◽  
Coefficient Of Thermal Expansion ◽  
Glass Melting ◽  
Glass Network ◽  
Iron Phosphate ◽  
Chemical Durability ◽  
Raw Material

As the part of investigation for immobilization of the sludge as one of the radioactive wastes arising from the treatment of contaminated water at Fukushima Dai-ichi nuclear power plant, applicability of vitrification method has been evaluated as a candidate technique. The aim of this study is to evaluate the influence of NaCl as one of the main constituents of sludge, on glass formation and glass properties. Two kinds of iron phosphate glass (IPG) media in the xFe2O3-(100-x)P2O5, with x = 30 and 35 (mol%) were chosen and the glass formation, structure and properties including density, coefficient of thermal expansion, glass transition temperature, onset crystallization temperature and chemical durability of NaCl-loaded IPG were studied. The results are summarized as follows. Sodium chloride, NaCl could be loaded into IPG medium as Na2O and Cl contents and their loading ratio could be up to 19 and 15 mol%, respectively. Majority of Cl content of raw material NaCl was thought to be volatilized during glass melting. Loading NaCl into IPG induces to depolymerize glass network of phosphate chains, leads to decrease both glass transition and onset crystallization temperatures, and to increase coefficient of thermal expansion. NaCl-loaded IPG indicated good chemical durability in case of using 35Fe2O3-65P2O5 medium.

Proposal for a material with negative thermal expansion

2016 ◽  
Vol 30 (32) ◽  
pp. 1650238
Author(s):  
Mikrajuddin Abdullah
Keyword(s):  
Thermal Expansion ◽  
Glass Transition ◽  
Transition Temperature ◽  
Metal Organic Framework ◽  
Negative Thermal Expansion ◽  
Lennard Jones ◽  
Model Predictions ◽  
Metal Organic ◽  
Organic Framework

I propose a model of a material that exhibits negative thermal expansion (NTE) properties and criteria for the occurrence of linear and volumetric NTE. I derived the criteria for an arbitrary force between rigid units in the material. These criteria are also discussed specifically for the Lennard–Jones (6–12) potential and in more detail for metal–organic framework (MOF) materials comprising rigid units connected by organic linkers. Qualitatively, the model predictions can explain some observed results. Surprisingly, the model can produce equations for the transition temperature from NTE to positive thermal expansion (PTE), [Formula: see text] K, which is exactly the same as the temperature at which the glass transition begins to occur in most polymers, i.e., [Formula: see text] K.

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