Accuracy in the experimental calorimetric study of the crystallization kinetics and predictive transformation diagrams: Application to a Ga–Te amorphous alloy

The uncertainties inherent to experimental differential scanning calorimetric data are evaluated. A new procedure is developed to perform the kinetic analysis of continuous heating calorimetric data when the heat capacity of the sample changes during the crystallization. The accuracy of isothermal calorimetric data is analyzed in terms of the peak-to-peak noise of the calorimetric signal and base line drift typical of differential scanning calorimetry equipment. Their influence in the evaluation of the kinetic parameter is discussed. An empirical construction of the time-temperature and temperature-heating rate transformation diagrams, grounded on the kinetic parameters, is presented. The method is applied to the kinetic study of the primary crystallization of Te in an amorphous alloy of nominal composition Ga20Te80, obtained by rapid solidification.

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A Differential Scanning Calorimetric Study of Carbide Transition in 10Cr Tempered Martensitic Steels

MRS Proceedings ◽

10.1557/opl.2015.586 ◽

2015 ◽

Vol 1754 ◽

pp. 37-42

Author(s):

H.C. Wang

Keyword(s):

Electron Microscopy ◽

Carbide Precipitation ◽

The Other ◽

Differential Scanning Calorimetric ◽

Calorimetric Study ◽

Martensitic Steels ◽

Scanning Calorimetry ◽

Precise Understanding ◽

Kinetics Of

ABSTRACTThe process and kinetics of carbide precipitation upon tempering of an Fe-10Cr-0.15C (wt.%) alloy fabricated from high-purity components has been studied. Differential scanning calorimetry reveals three exotherms in a temperature range of 100-700°C. Using advanced electron microscopy and Kissinger analysis, the exothermic processes have been interpreted. Cementite precipitated first upon tempering at temperatures as low as 200°C; M7C3 and M23C6 appear at higher temperatures, precipitating at approximately the same time but on different sites (M7C3 within grains and laths and M23C6 on grain and lath boundaries). Subsequently, the more stable M23C6 coarsens at the expense of M7C3, which dissolves. The first exotherm was interpreted as being related to the precipitation of cementite whilst the other two overlapping exotherms were interpreted as relating to the concurrent precipitation and coarsening of M7C3 and M23C6, respectively. In-situ SEM and TEM observation is being conducted in order to obtain a more precise understanding and further validate the interpretation of the DSC results.

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Karakteristik Protein dan Nitrogen Non Protein Daging Ikan Cucut Lanyam (Charcharhinus limbatus) (Characteristics of Protein and Non Protein Nitrogen in Lanyam Shark Muscle)

Fish Scientiae ◽

10.20527/fs.v1i1.1175 ◽

2016 ◽

Vol 1 (1) ◽

pp. 1

Author(s):

Yuspihana Fitrial

Keyword(s):

Muscle Protein ◽

Protein Solubility ◽

Differential Scanning Calorimetric ◽

Calorimetric Study ◽

Solubility Curve ◽

Scanning Calorimetry ◽

Protein Nitrogen ◽

Differential Scanning Calorimetry Study ◽

Nitrogen Levels ◽

Washing Process

<p>The aim of these research were to study the characteristics of protein and non protein nitrogen contained in Lanyam shark muscle, to obtain the protein solubility curve and iso-electric point. This research begins with the analysis of protein solubility of shark muscle at several levels of pH (from 1.5-12 with intervals of 0.5),. Then, performed classification of shark muscle protein nitrogen solubility in some solvents by using the classification Osborn, to observed the influence of the process of washing and boiling on non-protein nitrogen and urea in shark muscle and to study the thermal stability of muscle protein with differential scanning calorimetric study.</p>Based on protein solubility of Lanyam muscle at pH 1.5 to 12 obtained two points which is minimum solubility at pH 4.5 and pH 9. Based on the classification Osborn, Lanyam muscle contained albumin (28.64%), globulin (13:44%), prolamin (03.29%), glutelin (33.70%). Observation of non-protein nitrogen levels indicated that the washing process was very effective to reduce non-protein nitrogen levels up to 62.34% and urea levels up to 58% . Differential Scanning Calorimetry Study of Lanyam mince showed two types of protein that has a different stability to heat and after added 2.5% NaCl formed a peak which is a fusion of both these proteins

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Kinetics Study on Non-Isothermal Crystallization of Amorphous Alloy Mg65Cu15Ag10Y10

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.413.432 ◽

2011 ◽

Vol 413 ◽

pp. 432-438

Author(s):

Xiao Jun Wang ◽

Tian Dong Xia ◽

Xue Ding Chen

Keyword(s):

Activation Energy ◽

Amorphous Alloy ◽

Heating Rate ◽

Volume Fraction ◽

Strong Dependence ◽

Continuous Heating ◽

Heating Rates ◽

Scanning Calorimetry ◽

Local Activation ◽

Local Activation Energy

The crystallization kinetics of amorphous alloy Mg65Cu15Ag10Y10has been studied by differential scanning calorimetry in the mode of continuous heating annealing. It is found that both DSC curves and activation energy show a strong dependence on the heating rate. The activation energy for crystallization are determined as 186.1 and 184.4 KJ mol−1for the heating rates β=5-20 Kmin−1, and 107.5 and 110.0 KJmol−1for the heating rates β=20-80Kmin−1, when using the Kissinger equation and the Ozawa equation, respectively. Local activation energy at any volume fraction crystallized was obtained by the general Ozawa's isoconversional method. The average value of local activation energy for heating rates ranging from 5 to 20Kmin−1is 180.9 KJ mol−1and for heating rates ranging between 20 and 80Kmin−1is 110.2 KJ mol−1. Using the Suriñach curve fitting procedure, the kinetics mode was specified. The JMA kinetics is manifested as a rule in the early stages of the crystallization. The JMA exponent,n, initially being larger than 4 and continuously decreases to about 2 along with the development of crystallization. The NGG-like mode dominates in the advanced stages of the transformation. These two modes are mutually independent. The proportion between the JMA-like and the NGG-like modes is related to the heating rate.

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A Differential Scanning Calorimetric Study of the Mg-Cu-Y System

Materials Science Forum ◽

10.4028/www.scientific.net/msf.706-709.1215 ◽

2012 ◽

Vol 706-709 ◽

pp. 1215-1220 ◽

Cited By ~ 1

Author(s):

Mohammad Mezbahul-Islam ◽

Elhachmi Essadiqi ◽

Mamoun Medraj

Keyword(s):

Differential Scanning Calorimetry ◽

Metallic Glass ◽

Thermodynamic Modeling ◽

Differential Scanning Calorimetric ◽

Phase Assemblage ◽

Calorimetric Study ◽

Solidification Behavior ◽

Scanning Calorimetry ◽

Ternary Compounds ◽

Melting Temperatures

The Mg-Cu-Y system has been experimentally investigated using differential scanning calorimetry (DSC). Vertical sections and phase assemblage diagrams are calculated using thermodynamic modeling. Solidification behavior of the key alloys was discussed in light of the thermodynamic calculation. Melting temperatures of two of the ternary compounds; Mg18CuY and Mg4CuY, are predicted using the modified thermodynamic database of this system. Key words: Mg alloys, Bulk metallic glass, Differential scanning calorimetry, Thermodynamic modeling.

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Analysis of Primary Crystallization in Amorphous Aluminum Alloys

MRS Proceedings ◽

10.1557/proc-754-cc10.3 ◽

2002 ◽

Vol 754 ◽

Author(s):

John H. Perepezko ◽

William S. Tong ◽

Joe Hamann ◽

Rainer J. Hebert ◽

Harald R. Rösner ◽

...

Keyword(s):

Isothermal Annealing ◽

Fine Powder ◽

Primary Crystallization ◽

Onset Temperature ◽

Continuous Heating ◽

Scanning Calorimetry ◽

Coarse Powder ◽

Notable Effect ◽

Intense Deformation

ABSTRACTThe annealing response of amorphous Al based alloy samples were investigated to assess the role of the as-quenched state on primary crystallization of Al nanocrystals(nc). Continuous heating differential scanning calorimetry (DSC) traces of amorphous Al87Ni10Ce3 powders were compared to those from melt spun ribbon (MSR) to examine the effect of sample subdivision on primary crystallization. While the powders exhibited the same onset temperature as MSR, thermal cycling experiments show fine powder sizes reacting at the onset temperature and coarse powder sizes with the lowest melt quench rate transforming at the highest primary reaction temperature. In Al92Sm8 MSR, a kinetics analysis of Al nc distributions indicates a notable effect of the as-quenched state on primary crystallization during isothermal annealing. With Al88Y7Fe5 MSR intense deformation can induce thedevelopment of an Al nc distribution without thermal annealing. In each case examined, the results support the inclusion of quenched in clusters in the analysis of primary crystallization reactions.

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A differential scanning calorimetric study of the thermal behaviour of bovine β-lactoglobulin at temperatures up to 160 °C

Journal of Dairy Research ◽

10.1017/s0022029900021713 ◽

1981 ◽

Vol 48 (2) ◽

pp. 293-302 ◽

Cited By ~ 82

Author(s):

Jacob N. de Wit ◽

Gijsbert Klarenbeek

Keyword(s):

Thermal Behaviour ◽

Conformational Changes ◽

Temperature Shift ◽

Differential Scanning Calorimetric ◽

Calorimetric Study ◽

Scanning Calorimetry ◽

Maximum Heat ◽

Β Lactoglobulin ◽

Endothermal Peak ◽

Dsc Curves

SummaryThe thermal behaviour of β-lactoglobulin was studied by differential scanning calorimetry (DSC) in the temperature range 40–160 °C. The DSC curves revealed, in addition to the usually observed denaturation peak near 80 °C, a distinct endothermal peak between 130 and 150 °C. When the pH was increased from 6·5, the area under the peak near 80 °C (denaturation heat) decreased significantly, whereas the peak area near 140 °C increased. The temperature of maximum heat absorption in the peaks near both 80 and 140 °C gradually increased as the pH decreased. Addition of sugars and variation of the heating rate both caused a temperature shift of the endothermal heat effect at 140 °C, similar to that at 80 °C. No peak near 140 °C was observed when β-mercapto-ethanol was added to the β-lactoglobulin solution before scanning. The origin and nature of the high temperature denaturation peak is discussed in terms of conformational changes of the protein.

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Crystallization Behavior of Mechanically Alloyed Zr-Cu-Al-Ni Glass Composites Containing Second-Phase ZrC Particles

MRS Proceedings ◽

10.1557/proc-754-cc6.19 ◽

2002 ◽

Vol 754 ◽

Author(s):

S. Deledda ◽

J. Eckert ◽

L. Schultz

Keyword(s):

Mechanical Alloying ◽

Crystallization Behavior ◽

Volume Fraction ◽

Nominal Composition ◽

Second Phase ◽

Calorimetric Data ◽

Mechanically Alloyed ◽

Scanning Calorimetry ◽

Avrami Model ◽

Dissolved Carbon

ABSTRACTWe report on mechanical alloying of elemental powders with nominal composition Zr55Cu30Al10Ni5 together with up to 30 vol.% of ZrC particles which results in the formation of a metallic glass matrix in which the carbide particles are homogeneously dispersed and, at the same time, reduced to nanometer size. The thermal stability is investigated by isochronal differential scanning calorimetry and is found to be strongly affected by increasing the ZrC volume fraction. Comparison with calorimetric data for single-phase mechanically alloyed Zr-Cu-Al-Ni-C glassy powders suggests that dissolved carbon, originating from non-negligible ZrC-dissolution processes during mechanical alloying, is responsible for the changes in the glass transition and the crystallization behavior. Isothermal calorimetric data are also presented and discussed in the framework of the Johnson-Mehl-Avrami model. The carbon atoms dissolved in the glassy phase are suggested to slow down the kinetics of overall crystallization. On the other hand, for large ZrC volume fractions nucleation of crystalline phases is promoted by the second-phase particles and changes in the Avrami exponent from n = 4 to n = 3 suggest that the nucleation rate approaches zero after the early stages of crystallization.

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