Composition Dependence of Phase Separation and Crystallization in Deeply Undercooled Zr-(Ti-)Cu-Ni-Al Alloys

2000 ◽  
Vol 644 ◽  
Author(s):  
Andreas A. Kündig ◽  
Jörg F. Löffler ◽  
William L. Johnson
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Scale Up ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Glass Forming ◽  
The Difference ◽  
Xrd Patterns ◽  
Thermal Stability Of

AbstractDifferent bulk glass forming alloys in the neighborhood of Zr52.5Cu17.9Ni14.6Al10Ti5 (Vit105) have been investigated by differential scanning calorimetry (DSC), x-ray diffraction (XRD) and small-angle neutron scattering (SANS). Along the Ti/Al line in composition space, Zr52.5Cu17.9Ni14.6Al10−xTi5+x with – ≤ x ≤ +2.5, the glass transition temperature, Tg, and the undercooled liquid regime (the difference between the first crystallization temperature and the glass transition temperature) continually decrease with increasing x. SANS measurements of annealed alloys show interference maxima, giving evidence for decomposition on the nanometer scale, up to a critical temperature Tc. In contrast to Tg, Tc increases with x and thus intercepts with Tg in the range –2.5 ≤ x ≤ –1.25, depending on the time scale of the experiment. At this composi- tion, significant changes in DSC traces and XRD patterns are observed. Additional isothermal DSC experiments show that the onset times for crystallization are significantly different for temperatures below and above Tc. We conclude that Tc, respectively the relation between Tc and Tg, determines the crystallization behavior and the thermal stability of these bulk metallic glasses.

Thermal Behavior of Chalcogenide glasses Te90Se10 and Se90Te10

2015 ◽  
Vol 7 (02) ◽  
pp. 113-118
Author(s):  
Arvind Kumar Verma ◽  
Anchal Srivastava ◽  
R. K Shukla ◽  
K. C Dubey
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Glass Forming Ability ◽  
Scanning Calorimetry ◽  
Glass Forming ◽  
The Difference ◽  
Thermal Stability Of

In the present research work melt quenching method has been adopted to prepare the glassy Te-rich (Te90Se10) and Se-rich (Se90Te10 ) Chalcogenide at a pressure of 10-2 Torr with constant Temperature at 1000°C for 8 hours. Devitrification characteristics of the pure glassy Chalcogenide Te90Se10 and Se90Te90 were investigated by using Differential scanning Calorimetry (DSC) 4000 Perkin Elmer. All the measurements carried out at fixed heating rate 10 0C/min under non-isothermal conditions. The Glass transition temperature (Tg) and other thermal properties were examined by temperature modulated differential scanning Calorimetry at 40 oC to 445 oC. Glass transition temperature (Tg) represents the strength or rigidity of the glass structure. Tg affords valuable information on the thermal stability of the glassy state but Tg alone does not give any information on the glass forming tendency. The difference of the Peak crystallization temperature (Tp) and Glass transition temperature (Tg) is a strong indication of the thermal stability. The higher the value of Tc and Tg the greater is the thermal stability. Glass transition temperature (Tg=2160C) of Tellurium rich (Te90Se10) is more than Glass transition temperature (Tg=730C) of Selenium rich (Se90Te90) due to semi metallic nature of Tellurium. The difference of (Tp-Tg) is a strong indicator of both the thermal stability and Glass forming ability (GFA). Higher the value of (Tp-Tg), higher is the thermal stability and GFA because higher values of this difference indicate more kinetic resistance to the crystallization. Glass forming ability (GFA) and thermal stability of Te90Se10 is greater than Se90Te90. For memory and switching materials, glass thermal stability and GFA parameters are very important. Intensity of Se-rich (Se90Te10) is more than Te-rich (Te90Se10) and both samples are polycrystalline in nature.

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.

New Stable Iodide Glasses in the Cd-As-I and Cd-As-Ge-I Systems

1989 ◽  
Vol 172 ◽  
Author(s):  
Jong Heo ◽  
George H. Sigel
Keyword(s):  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Optical Fibers ◽  
Liquid Water ◽  
Infrared Region ◽  
Chemical Durability ◽  
Scanning Calorimetry ◽  
Glass Forming

AbstractIodide glasses presently being investigated suffer from their poor glass forming abilities, thermal instabilities and general lack of chemical durability. Glasses in the Cd-As-I and Cd-As-Ge-I systems are investigated in this study for the purpose of developing water-resistant, thermally stable iodide glasses and optical fibers. Differential scanning calorimetry(DSC) showed that glasses in these systems have glass transition temperature(Tg) values above 300°C. Devitrification of glasses during cooling and reheating can be suppressed by incorporating small amount of Ge atoms into ternary Cd-As-I glasses. They are transparent up to 14μm in the infrared region with excellent durability against liquid water at 90°C.

Rare Earth Elements on Glass-Forming Ability and Thermal Stability of Cu-Zr-Al Metallic Glass

2011 ◽  
Vol 688 ◽  
pp. 426-430 ◽  
Author(s):  
Yan Fang Wang ◽  
Li Li ◽  
Chuan Sun ◽  
Qing Long Lu ◽  
Zhi Qiang Shi
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Rare Earth ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Metallic Glass ◽  
Rare Earth Elements ◽  
Glass Forming Ability ◽  
Glass Forming ◽  
Thermal Stability Of

The rare earth elements (RE= Y, Sm, La, Ce) were used as alloying materials in Cu50Zr45Al5BMG, and their influences on the glass-forming ability and thermal stability were studied in this paper. All the samples remained in full metallic glass state with minor additions of Y, Sm and La. Increasing the amount of RE additions, the Cu10Zr7and Zr2Cu phases precipitated and glass transition temperatureTgand crystallization temperatureTxsignificantly decreased. The reduced glass transition temperature Trg=Tg/Tlranged from 0.592 to 0.611 and the γ parameter ranged from 0.393 to 0.409.

scholarly journals Reduced Glass-Transition Temperature versus Glass-Forming Ability in FeCoB-Based Amorphous Alloys

2016 ◽  
Vol 61 (4) ◽  
pp. 1957-1962 ◽  
Author(s):  
M. Nabiałek
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Glass Forming Ability ◽  
Scanning Calorimetry ◽  
Dsc Studies ◽  
Glass Forming ◽  
Wide Range ◽  
Temperature Ranges ◽  
The Relationship

AbstractThis work presents studies concerning the relationship between reduction of glass transition temperatureTrgand the glass-forming ability of FeCoB-based alloys. On the basis of theoretical considerations, Turnbull [1] determined the reduced glass transition temperature (Tg/Tl) as being 2/3 of the Vogel–Fulcher–Tammann (VFT) temperature; since then, continuous research has been carried out, aiming to calculate the Trg parameter and describe its relationship with glass-forming ability. In the majority of research papers, the reduced glass transition temperature is calculated from the relationshipTg/Tm, proposed by Uhlmann and Davies [2, 3]. On the basis of differential scanning calorimetry (DSC) studies, undertaken in this current work, the values of the following temperatures have been found:Tg,Tx, Tmand Tl, in addition to the temperature ranges:ΔTx,ΔTmandΔTl. The correlation between:Tg/Tm,Tg/Tland the glass-forming ability also has been discussed. Finally, for the investigated alloys, it has been found that the relationship proposed by Turnbull is reliable over a wide range ofΔTm.

Structure and Low Melting Property of Vanadate Tellurite Glass

2010 ◽  
Vol 663-665 ◽  
pp. 1229-1233 ◽  
Author(s):  
Shi Yong Luo ◽  
Wen Cai Xu ◽  
Xin Lin Zhang ◽  
Li Xia Huo
Keyword(s):  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Tellurite Glass ◽  
Melting Process ◽  
Glass Frit ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

The glasses (80-x)TeO2·xV2O5·20MO (M=Sn, Bi, Ca, Na and K) had been examined as potential replacements for PbO-based glass frits with low firing temperature. The glasses with TeO2 0-44 mol%, and V2O5 39-82 mol% are not suitable for glass frit since they are easy to crystallize. The glasses with the content of the TeO2 54-74 mol%, and the V2O5 9-29 mol% were investigated by differential scanning calorimetry, X-ray diffraction, infrared spectra and fluidity evaluation experiments. The glasses possess appropriate fluidity and do not crystallize in the re-melting process at 723-753 K. The glass transition temperature of the glasses is at 544-578 K. The structure of the glasses is layer upon layer mainly connected by the structure units of [VO4] and [TeO3]. Other modifier ions locate mainly between the layers. The isolated V=O band from the VO5 bipyramids is not occurred in the vitreous structure of the glasses.

scholarly journals Thermal analysis: basic concept of differential scanning calorimetry and thermogravimetry for beginners

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Nurul Fatahah Asyqin Zainal ◽  
Jean Marc Saiter ◽  
Suhaila Idayu Abdul Halim ◽  
Romain Lucas ◽  
Chin Han Chan
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Commercial Application ◽  
Scanning Calorimetry ◽  
Teaching Activities ◽  
Sample Decomposition ◽  
Calibration Baseline

AbstractWe present an overview for the basic fundamental of thermal analysis, which is applicable for educational purposes, especially for lecturers at the universities, who may refer to the articles as the references to “teach” or to “lecture” to final year project students or young researchers who are working on their postgraduate projects. Description of basic instrumentation [i.e. differential scanning calorimetry (DSC) and thermogravimetry (TGA)] covers from what we should know about the instrument, calibration, baseline and samples’ signal. We also provide the step-by-step guides for the estimation of the glass transition temperature after DSC as well as examples and exercises are included, which are applicable for teaching activities. Glass transition temperature is an important property for commercial application of a polymeric material, e.g. packaging, automotive, etc. TGA is also highlighted where the analysis gives important thermal degradation information of a material to avoid sample decomposition during the DSC measurement. The step-by-step guides of the estimation of the activation energy after TGA based on Hoffman’s Arrhenius-like relationship are also provided.

scholarly journals Characterization of the Interface Between the Bulk Glass Forming Alloy Zr41Ti14Cu12Ni10Be23 with Pure Metals and Ceramics

2000 ◽  
Vol 15 (7) ◽  
pp. 1617-1621 ◽  
Author(s):  
Jan Schroers ◽  
Konrad Samwer ◽  
Frigyes Szuecs ◽  
William L. Johnson
Keyword(s):  
Sessile Drop ◽  
Bulk Glass ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Glass Forming ◽  
Processing Times ◽  
Thermal Stability Of

The reaction of the bulk glass forming alloy Zr41Ti14Cu12Ni10Be23 (Vit 1) with W, Ta, Mo, AlN, Al2O3, Si, graphite, and amorphous carbon was investigated. Vit 1 samples were melted and subsequently solidified after different processing times on discs of the different materials. Sessile drop examinations of the macroscopic wetting of Vit 1 on the discs as a function of temperature were carried out in situ with a digital optical camera. The reactions at the interfaces between the Vit 1 sample and the different disc materials were investigated with an electron microprobe. The structure and thermal stability of the processed Vit 1 samples were examined by x-ray diffraction and differential scanning calorimetry. The results are discussed in terms of possible applications for composite materials.

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