Solid-Solid Phase Transformations and Their Kinetics in Ti-Al-Nb Alloys

The application of light-weight intermetallic materials to address the growing interest and necessity for reduction of CO2 emissions and environmental concerns has led to intensive research into TiAl-based alloy systems. However, the knowledge about phase relations and transformations is still very incomplete. Therefore, the results presented here from systematic thermal analyses of phase transformations in 12 ternary Ti-Al-Nb alloys and one binary Ti-Al measured with 4–5 different heating rates (0.8 to 10 °C/min) give insights in the kinetics of the second-order type reaction of ordered (βTi)o to disordered (βTi) as well as the three first-order type transformations from Ti3Al to (αTi), ωo (Ti4NbAl3) to (βTi)o, and O (Ti2NbAl) to (βTi)o. The sometimes-strong heating rate dependence of the transformation temperatures is found to vary systematically in dependence on the complexity of the transformations. The dependence on heating rate is nonlinear in all cases and can be well described by a model for solid-solid phase transformations reported in the literature, which allows the determination of the equilibrium transformation temperatures.

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Crystalline forms of silver iodide II: Determination of phase transformations

Journal of the Serbian Chemical Society ◽

10.2298/jsc0709857v ◽

2007 ◽

Vol 72 (8-9) ◽

pp. 857-868 ◽

Cited By ~ 7

Author(s):

Marija Vukic ◽

Dragan Veselinovic ◽

Vesna Markovic

Keyword(s):

Phase Transition ◽

Phase Transformations ◽

Heating Rate ◽

Silver Iodide ◽

Room Temperature ◽

Sample Heating ◽

Crystalline Forms

In order to obtain appropriate forms of AgI (?- and ?-), a procedure was developed to synthesize AgI at room temperature (23?C), whereby samples of varying crystallographic purity and of varying crystallographic contents of the different forms were obtained. This paper presents the results of investigations of the influence of the manner of preparation of ?-AgI and ?-AgI samples and the sample heating rate on the phase transformations and their temperatures. During the heating of non-ground, ground and pressed synthesized AgI samples, the phase transformations and the corresponding temperatures for one ?-AgI and four ?-AgI samples with different ?-AgI contents (representing a crystallographic impurity) were identified. The following phase transformations were observed for the non-ground AgI samples: ?-AgI ? ?-AgI at 149.6?C (for the ?-AgI sample) and ?-AgI ? ?-AgI at 148.7?C or 148.2?C for the ?-AgI samples with a minimum content of ?-AgI (less than 7 %), as a crystallographic impurity. The phase transition ?-AgI ? ?-AgI was irreversible because ?-AgI was obtained whenever the samples were heated up to 260?C. Manual sample grinding, as well as pressing at p1 = 650 MPa and p2 = 900 MPa resulted in the ?-AgI ? ?-AgI phase transition in all the investigated cases. .

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Determination of Solidification Parameters Used for the Prediction of the Thixoformability of Several Steel Alloys

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.116-117.54 ◽

2006 ◽

Vol 116-117 ◽

pp. 54-57 ◽

Cited By ~ 4

Author(s):

Jacqueline Lecomte-Beckers ◽

Ahmed Rassili ◽

Marc Robelet ◽

Claude Poncin ◽

R. Koeune

Keyword(s):

Differential Scanning Calorimetry ◽

Heating Rate ◽

Liquid Fraction ◽

Heating Rates ◽

Scanning Calorimetry ◽

Steel Alloys ◽

Fraction Versus ◽

Solidification Parameters ◽

Industrial Heating

This paper focuses on the liquid fraction curves of several steels and the correlation between liquid fraction, temperature and heating rate. The work has been performed along two main axes. First, the solid fraction versus temperature has been obtained experimentally by differential scanning calorimetry (DSC), limited to low heating rates. Then, a shift of the liquid fraction curves has been noticed at high industrial heating rates. The quantification of this effect could not be carried out by DSC and required the elaboration of another experimental device.

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THE HEATING RATE IMPACT ON PARAMETERS CHARACTERISTIC OF STEEL BEHAVIOUR UNDER FIRE CONDITIONS

Journal of Civil Engineering and Management ◽

10.3846/13923730.2006.9636403 ◽

2006 ◽

Vol 12 (4) ◽

pp. 269-275 ◽

Cited By ~ 7

Author(s):

Zoja Bednarek ◽

Renata Kamocka

Keyword(s):

Heating Rate ◽

Steel Structure ◽

Steel Structures ◽

Absolute Temperature ◽

Strength Analysis ◽

Test Results ◽

Heating Rates ◽

Linear Temperature ◽

Strength Tests

The behaviour of steel structure components within a high temperature field depends not only on the absolute temperature, but also on the temperature vs time function and on the heating rate, dT/dτ. The research objective is the determination of the heating rate impact on selected strength parameters of structural steels. Tests were performed under conditions of a linear temperature increase with different heating rates and with a constant stress value, σ/fy . After strength tests, the samples were subjected to metallography. Test results proved that the heating rate makes a significant impact on parameters that determine the steel structure bearing capacity at higher temperatures and that the heating rate should be accounted for in the strength analysis of steel structures exposed to high temperatures.

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Determination of Eutectoid Transformation Temperatures in Ductile Cast Iron

Archives of Foundry Engineering ◽

10.1515/afe-2015-0078 ◽

2015 ◽

Vol 15 (4) ◽

pp. 51-54 ◽

Cited By ~ 1

Author(s):

A.W. Orłowicz ◽

A. Trytek ◽

M. Mróz ◽

M. Tupaj

Keyword(s):

Cast Iron ◽

Cooling Rate ◽

Ductile Cast Iron ◽

Eutectoid Transformation ◽

Heating Rates ◽

Cooling Rates ◽

Metallographic Examination ◽

Transformation Temperatures ◽

Rate Of Cooling

Abstract The paper proposes a methodology useful in verification of results of dilatometric tests aimed at determination of temperatures defining the start and the end of eutectoid transformation in the course of ductile cast iron cooling, based on quenching techniques and metallographic examination. For an industrial melt of ductile cast iron, the effect of the rate of cooling after austenitization at temperature 900°C carried out for 30 minutes on temperatures TAr1start and TAr1end was determined. The heating rates applied in the study were the same as the cooling rates and equaled 30, 60, 90, 150, and 300°C/h. It has been found that with increasing cooling rate, values of temperatures TAr1start and TAr1end decrease by several dozen degrees.

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An FT-IR Method for Performing Dynamic Kinetic Experiments

Applied Spectroscopy ◽

10.1366/0003702884429300 ◽

1988 ◽

Vol 42 (4) ◽

pp. 655-658 ◽

Cited By ~ 14

Author(s):

Randy W. Snyder ◽

C. Wade Sheen

Keyword(s):

Activation Energy ◽

Kinetic Parameters ◽

Heating Rate ◽

Heating Rates ◽

Calculated Activation Energy ◽

Ft Ir ◽

Calculated Activation

A method is shown for the determination of kinetic parameters from dynamic FT-IR experiments. The effect heating rate has on the reproducibility of the calculated activation energy is discussed. The curing of PMDA/ODA polyimide at several heating rates is given as an example.

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The Effects of Heating Rate and Cold Work on the Development of Dual-Phase Steel Microstructures

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.922.755 ◽

2014 ◽

Vol 922 ◽

pp. 755-760

Author(s):

L.S. Thomas ◽

David K. Matlock ◽

John G. Speer

Keyword(s):

Heating Rate ◽

Dual Phase Steel ◽

Thermomechanical Processing ◽

Cold Work ◽

Carbon Steels ◽

Dual Phase ◽

Low Carbon ◽

Heating Rates ◽

Contributing Factors ◽

Transformation Temperatures

The effects of heating rate and prior cold work on the development of dual-phase steel microstructures in three low carbon steels were evaluated with samples processed on a Gleeble 3500 thermomechanical processing simulator. The nominally 0.2 wt pct carbon steels included a plain carbon steel and modified alloys incorporating higher manganese contents, boron additions, and microalloy additions. Each alloy was prepared with two different cold rolled reductions. Heating rates from 1 to 1000 oC/s were selected to span the rates typically experienced in conventional furnace heat treating up to rates for induction heating. Critical transformation temperatures were obtained from dilatometric curves. Dual-Phase microstructures after heat treatment with different heating rates were compared. Transformation temperatures decreased with an increase in cold work and increased with an increase in heating rate. The steels with higher manganese and carbon additions exhibited lower Ac3 values across all heating rates and the steels with higher silicon higher Ac1 temperatures across all heating rates. Ac1 increased less than Ac3 with increasing heating rate. The increase in transformation temperatures between 100 and 1000 °C/s was smaller than values exhibited over other increments in heating rate, and decreased in one steel; contributing factors were identified for this behavior.

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218. Determination of Formaldehyde Using Solid Phase Microextraction for Both Instantaneous and Timeweighted Average Sampling

10.3320/1.2762606 ◽

1999 ◽

Author(s):

P.A. Martos ◽

J. Pawliszyn

Keyword(s):

Solid Phase Microextraction ◽

Solid Phase ◽

Average Sampling

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Modern determinants of endometrium hyperplastic processes pathogenesis

HEALTH OF WOMAN ◽

10.15574/hw.2016.111.137 ◽

2016 ◽

pp. 137-142

Author(s):

V.O. Benyuk ◽

◽

V.M. Goncharenko ◽

T.R. Nykoniuk ◽

◽

...

Keyword(s):

Conservative Therapy ◽

Solid Phase ◽

Research Direction ◽

Immunohistochemical Method ◽

Results Of Treatment ◽

Treatment And Prevention ◽

Receptor Phenotype ◽

The Relationship ◽

Endometrial Proliferation

The objective: to еxplore the relationship between the activity of endometrial proliferation and the state of the local immune response in the uterus in the conditions berprestasi process. Patients and methods. Examined 228 women of reproductive and perimenopausal age with endometrial pathology using ultrasound and then performing hysteroresectoscopy. Determination of the concentrations of the cytokines IL-1, IL-2, IL-6 and TNF was performed by solid phase ELISA. Results. Found a trend that confirms the loss of sensitivity to hormones at the stage of malignancy of the endometrium and can be used as diagnostic determinants in determining the nature of intrauterine pathology and criterion of the effectiveness of conservative therapy. Conclusion. Improving etiopatogenetice approach to the therapy of hyperplastic proce.sses of endometrium with determination of receptor phenotype of the endometrium is a research direction in modern gynecology, which will help to improve the results of treatment and prevention of intrauterine pathology. Key words: endometrial hyperplasia,the receptors for progesterone and estrogen, immunohistochemical method.

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