Investigation of phase transformations at elevated temperatures and pressures by differential thermal analysis in piston-cylinder apparatus

1966 ◽  
Vol 27 (1) ◽  
pp. 179-186 ◽  
Author(s):  
L.H. Cohen ◽  
W. Klement ◽  
G.C. Kennedy
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Phase Transformations ◽  
Elevated Temperatures ◽  
Piston Cylinder

scholarly journals Influence of the Al content on the phase transformations in Cu-Al-Ag alloys

2003 ◽  
Vol 28 (1) ◽  
pp. 33-38 ◽  
Author(s):  
A. T. Adorno ◽  
A. V. Benedetti ◽  
R. A. G. da Silva ◽  
M. Blanco
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Transition Temperature ◽  
Phase Transformations ◽  
Decomposition Reaction ◽  
Phase Decomposition ◽  
Stability Range ◽  
X Ray ◽  
Al Content ◽  
The Stability

The influence of the Al content on the phase transformations in Cu-Al-Ag alloys was studied by classical differential thermal analysis (DTA), optical microscopy (OM) and X-ray diffractometry (XRD). The results indicated that the increase in the Al content and the presence of Ag decrease the rate of the <FONT FACE=Symbol>b</font>1 phase decomposition reaction and contribute for the raise of this transition temperature, thus decreasing the stability range of the perlitic phase resulted from the b1 decomposition reaction.

An Automatic Selection of Segment Width for the Single Sensor Differential Thermal Analysis (SS-DTA) Based on Piecewise Linear Approximation Technique

2015 ◽  
Vol 658 ◽  
pp. 96-100 ◽  
Author(s):  
Wutipong Nieampradit ◽  
Sarawan Wongsa ◽  
Isaratat Phung-On
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Phase Transformations ◽  
Linear Approximation ◽  
Piecewise Linear ◽  
Research Work ◽  
Piecewise Linear Approximation ◽  
Approximation Technique ◽  
Analytical Formulae ◽  
Single Sensor

Single Sensor Differential Thermal Analysis (SS-DTA) is a novel non-destructive testing technique for studying and detecting the phase transformations and structural changes in materials. It uses only one temperature sensor to measure the temperature in a particular point of interest in the material during actual and simulated thermal processing of the material. SS-DTA compares the temperature recorded in a tested specimen against a reference thermal profile which can be generated either by analytical formulae or piecewise linear approximation. The main advantage of piecewise linear approximation over the analytical formulae is that it does not need the knowledge of tested material and processing conditions to optimally estimate the parameters of reference thermal history. On the other hand, in order to apply the piecewise linear approximation technique we must specify the segment width which is normally fixed at a nominal value of 1.5 seconds. We have recently found that this nominal value might not be an optimal choice for the segment width as it does not guarantee to give the best detectability of phase transformation. Therefore, in this research work we proposed a technique to automatically select an appropriate value of the segment width. The performance of proposed method has been evaluated by investigating the phase transformations of welded stainless steel SUS 321and SUS 304. It was found that the appropriate segment width could be ranging from 1.25-1.75 seconds and by using this selection technique, we could detect the differential temperature more accurately than when using the nominal value.

Phase Transformations in the Quenched Alloy Based on Orthorhombic Titanium Aluminide during Heating

2021 ◽  
Vol 316 ◽  
pp. 473-478
Author(s):  
A.G. Illarionov ◽  
S.V. Grib ◽  
A.A. Popov
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Phase Transformations ◽  
Titanium Aluminide ◽  
Phase State ◽  
Heating Temperature ◽  
Continuous Heating ◽  
Temperature Ranges ◽  
Orthorhombic Titanium ◽  
Heating Up

Phase transformations in the alloy based on the orthorhombic titanium aluminide (Ti-24,3Al-24,8Nb-1,4V-1,0Zr-0,6Mo-0,3Si – at. %) were studied by differential thermal analysis. The alloy was quenched from the different phase regions (β+O, β+O+α2+(Vω), β+α2, β) and was subjected to continuous heating up to . It was found that the heating temperature of the O-alloy, which determines its phase state during quenching, affects the temperature ranges, intensity, and stages of the phase transformations during subsequent heating.

scholarly journals Stabilization of rare earth elements (La, Nd, Pr, Ce) by ZrO2 concentrate

2018 ◽  
pp. 39-45
Author(s):  
V. B. Kul'metyeva ◽  
S. E. Porozova ◽  
V. G. Gilev ◽  
D. S. Vokhmyanin
Keyword(s):  
Thermal Analysis ◽  
Raman Spectroscopy ◽  
Differential Thermal Analysis ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Phase Transformations ◽  
Tetragonal Phase ◽  
Cubic Phases

The effect of annealing and sintering temperatures on the phase transformations of ZrO2was studied depending on the content of REE concentrate using differential thermal analysis, Raman spectroscopy andX-ray diffraction. It is shown that the introduction of REE concentrate in an amount of more than 15 wt. % stabilizes the tetragonal phase of ZrO2only at temperatures below 1200 °C. A further increase in temperature leads to destabilization of the tetragonal phase with the formation of the monoclinic and cubic phases of theLn2Zr2O7type isostructural compounds (n= La, Nd, ...) with the pyrochlore structure.Ill. 8. Ref. 19. Tab. 1.

Thermal Stability of the Lightweight Alkali Activated Chamotte

2016 ◽  
Vol 721 ◽  
pp. 332-336
Author(s):  
Laura Dembovska ◽  
Diana Bajare ◽  
Vilma Ducman ◽  
Girts Bumanis
Keyword(s):  
Thermal Stability ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Elevated Temperatures ◽  
Raw Materials ◽  
Mineralogical Composition ◽  
Density Range ◽  
Scrap Recycling ◽  
Alkali Activated ◽  
Thermal Stability Of

This study deals with the porous refractories based on alkali activated chamotte with addition of aluminium scrap recycling waste as a pore forming agent and firebrick sawing residues as a heat resistant filler for the application in temperature up to 850°C. These newly developed porous lightweight materials can be potentially used in the industrial field, since they display good thermal insulation, density range from 541 to 618 kg/m3 and resistance to elevated temperatures (material shrinkage at the temperature of 850°C did not exceed 0.05%). The refractoriness of alkali activated materials was studied by differential thermal analysis (DTA/TG) and dilatometry tests. Pore microstructure was examined by SEM. Mineralogical composition of the raw materials and physical properties of the produced samples were determined.

Differential Thermal Analysis of Complex Alloyed Brass

2019 ◽  
Vol 946 ◽  
pp. 282-286
Author(s):  
Raisa K. Mysik ◽  
Sergey V. Brusnitsyn ◽  
Andrey V. Sulitsin
Keyword(s):  
Thermal Analysis ◽  
Wear Resistance ◽  
Phase Transformation ◽  
Differential Thermal Analysis ◽  
Phase Transformations ◽  
Volume Fraction ◽  
High Wear Resistance ◽  
Second Phase ◽  
Technological Parameters ◽  
Structure Of Alloy

Copper alloys are widely used in mechanical engineering. In the article it is shown that the requirements of consumers to properties of alloys are constantly increasing. Complex alloyed brasses have a high wear resistance and corrosion resistance. The wear resistance is a basic property of an alloy. This characteristic determines the operating life of parts working in the wear conditions. The wear resistance is supported by phase composition of alloy, uniformity of distribution of phase in the structure of alloy, their volume fraction, their morphology and their dimensions. At present time the technology of continuous casting of ingots of alloys Cu59Zn34.6Mn3.5Al2.5Fe0.5Ni0.4, Cu70Zn13Mn7Al5Fe2Si2Pb1, Cu58Zn36Mn2Pb2Si1Al1 and Cu58Zn35Mn3Si1.5Ni1.5Pb1 is developed. However, the need to use new alloys for manufacturing of critical parts requires the development of technology for their production, taking into account the composition of alloy and the features of formation of structure. Therefore, it is necessary to establish well-founded technological parameters of melting and casting of ingots of complex alloyed brass Cu62Zn31.6Mn3Al2Si0.8Ni0.4Cr0.2. For determination of temperatures of phase transformations in the structure of alloy, the differential thermal analysis was carried out. Liquidus and solidus temperatures of alloy were determined. The crystallization range of alloy was established. This brass in a solid state undergoes two phase transformations. The temperature of the first phase transformation is 750 oC. The temperature of the second phase transformation is 515 oC. The obtained experimental data make it possible to describe the proposed mechanism of phase transformations in alloy Cu62Zn31.6Mn3Al2Si0.8Ni0.4Cr0.2 during crystallization and following cooling.

scholarly journals DTA measurements in the ternary Ag-Au-Ga system

2020 ◽  
pp. 21-21
Author(s):  
Dominika Jendrzejczyk-Handzlik ◽  
Piotr Handzlik
Keyword(s):  
Experimental Data ◽  
Thermal Analysis ◽  
Phase Diagram ◽  
Differential Thermal Analysis ◽  
Phase Transformations ◽  
Cross Sections ◽  
Calphad Method ◽  
Experimental Results ◽  
Zero Rate ◽  
Good Agreement

In this work, the ternary Ag-Au-Ga system was studied experimentally by differential thermal analysis (DTA). Measurements were carried out along two chosen cross-sections determined by the ratio of mole fractions XAg/XGa=1:1 and XAu/XGa=1:1 by applying Pegasus 404 apparatus form Netzsch. Experiments were performed at three rates: 1 K min-1, 5 K min-1 and 10 K min-1. Next, the obtained experimental results were used to estimate the temperatures of liquidus by applying extrapolation to zero rate. Moreover, the temperatures of invariant reactions and other phase transformations were investigated from DTA measurements which were carried out with the rate 1 K min-1. Finally, the experimental results were compared with the isopleths obtained from prediction and calculation of the phase diagram which were done by using CALPHAD method. Experimental data obtained in this work are in good agreement with the results of calculation.

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