Transformation Kinetics of α+γ2 to ß in Cu-Al Alloy after Cryogenic Treatment

2012 ◽  
Vol 562-564 ◽  
pp. 200-203
Author(s):  
Mai Shun Qi ◽  
Ya Li Li ◽  
Lai Lei Wu ◽  
Jian Hua Liu ◽  
Rui Jun Zhang
Keyword(s):  
Activation Energy ◽  
Phase Transformation ◽  
Heating Rate ◽  
Transformation Temperature ◽  
Volume Fraction ◽  
Cryogenic Treatment ◽  
Al Alloy ◽  
Transformation Kinetics ◽  
Transformation Time ◽  
Kinetics Of

The transformation temperature and time of α+γ2 to ß in a Cu-Al alloy after cryogenic treatment during heating were measured by DSC, and the transformation activation energy of α+γ2 to ß was also calculated. It is indicated that the Cu-Al alloy with heating rate of 10°C/min, the phase transformation onset and ending temperature is 561.75°C and 582.88°C, respectively, and the phase transformation time is126.6S. The phase transformation activation energy decreases with the increasing volume fraction of their phase transformation.

Study on the β1→α+β2 Transformation Kinetics of Ti-6Al-4V Alloy by DSC

2014 ◽  
Vol 508 ◽  
pp. 110-113
Author(s):  
Rong Hua Zhang ◽  
Biao Wu ◽  
Xiao Ping Zheng
Keyword(s):  
Activation Energy ◽  
Differential Scanning Calorimetry ◽  
Phase Transformation ◽  
Cooling Rate ◽  
Volume Fraction ◽  
Avrami Exponent ◽  
Transformation Kinetics ◽  
Cooling Process ◽  
Scanning Calorimetry ◽  
Kinetics Of

The temperature and duration of β1→α+β2 transformation of Ti-6Al-4V alloy in cooling process were measured by differential scanning calorimetry, and transformation activation energy and Avrami exponent of β1→α+β2 were also calculated. The results show that the cooling rate is in the range of 在5～20°C/min, the transformation temperature and the transformation duration β1→α+β2 transformation of Ti-6Al-4V alloy decreased with the increasing cooling rate, its transformation activation energy decreased with the increasing phase transformation volume fraction, and Avrami exponent was between 1 and 2 at 660°C.

scholarly journals Continuous Cooling Transformation Behaviour and Bainite Transformation Kinetics of 23CrNi3Mo Carburised Steel

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 48
Author(s):  
Wenjun Song ◽  
Min Lei ◽  
Mingpan Wan ◽  
Chaowen Huang
Keyword(s):  
Phase Transformation ◽  
Volume Fraction ◽  
Austenite Formation ◽  
Steel Matrix ◽  
Transformation Kinetics ◽  
Bainite Transformation ◽  
Continuous Cooling ◽  
The Matrix ◽  
Dimensional Growth ◽  
Kinetics Of

In this study, the phase transformation behaviour of the carburised layer and the matrix of 23CrNi3Mo steel was comparatively investigated by constructing continuous cooling transformation (CCT) diagram, determining the volume fraction of retained austenite (RA) and plotting dilatometric curves. The results indicated that Austenite formation start temperature (Ac1) and Austenite formation finish temperature (Ac3) of the carburised layer decreased compared to the matrix, and the critical cooling rate (0.05 °C/s) of martensite transformation is significantly lower than that (0.8 °C/s) of the matrix. The main products of phase transformation in both the carburised layer and the matrix were martensite and bainite microstructures. Moreover, an increase in carbon content resulted in the formation of lamellar martensite in the carburised layer, whereas the martensite in the matrix was still lath. Furthermore, the volume fraction of RA in the carburised layer was higher than that in the matrix. Moreover, the bainite transformation kinetics of the 23CrNi3Mo steel matrix during the continuous cooling process indicated that the mian mechanism of bainite transformation of the 23CrNi3Mo steel matrix is two-dimensional growth and one-dimensional growth.

scholarly journals Phase Transformation Kinetics of a FCC Al0.25CoCrFeNi High-Entropy Alloy during Isochronal Heating

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1015
Author(s):  
Jun Wang ◽  
Chen Wei ◽  
Haoxue Yang ◽  
Tong Guo ◽  
Tingting Xu ◽  
...  
Keyword(s):  
Phase Transition ◽  
Activation Energy ◽  
Phase Transformation ◽  
High Entropy Alloy ◽  
Transformation Kinetics ◽  
High Entropy ◽  
Phase Transformation Kinetics ◽  
Diffusion Controlled ◽  
Thermal Dilation ◽  
Kinetics Of

The phase transformation kinetics of a face-centered-cubic (FCC) Al0.25CoCrFeNi high-entropy alloy during isochronal heating is investigated by thermal dilation experiment. The phase transformed volume fraction is determined from the thermal expansion curve, and results show that the phase transition is controlled by diffusion controlled nucleation-growth mechanism. The kinetic parameters, activation energy and kinetic exponent are determined based on Kissinger–Akahira–Sunose (KAS) and Johnson–Mehl–Avrami (JMA) method, respectively. The activation energy and kinetic exponent determined are almost constant, indicating a stable and slow speed of phase transition in the FCC Al0.25CoCrFeNi high-entropy alloy. During the main transformation process, the kinetic exponent shows that the phase transition is diffusion controlled process without nucleation during the transformation.

scholarly journals Study on the Phase Transformation Kinetics of Sol-Gel DrivedTiO2Nanoparticles

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
H. Mehranpour ◽  
M. Askari ◽  
M. Sasani Ghamsari ◽  
H. Farzalibeik
Keyword(s):  
Activation Energy ◽  
Phase Transformation ◽  
Sol Gel ◽  
Rutile Phase ◽  
Transformation Kinetics ◽  
X Ray ◽  
Prepared Nanoparticles ◽  
Phase Transformation Kinetics ◽  
Diffusion Controlled ◽  
Kinetics Of

Titanium dioxide nanopowders were synthesized by the diffusion controlled sol-gel process (LaMer model) and characterized by DTA-TG, XRD, and SEM. The preparedTiO2nanoparticles have uniform size and morphology, and the phase transformation kinetics of obtained material was studied by interpretation of the X-ray diffraction patterns peaks on the base of Avrami equation. The stating point of anatase-rutile phase transformation temperature in the prepared nanoparticles was found between 100 and200°C. A decreasing trend on the intensity of X-ray peaks of anatase phase was observed up to600°Cwhen the presence of the rutile phase became predominant. Results indicated that the transition kinetics of the diffusion controlled prepared nanoparticles was begun at low temperature, and it can be concluded that the nucleation and growth sites in these particles were more than other. However, it has been found that the nucleation activation energy of rutile phase was 20 kj/mol, and it is the lowest reported activation energy.

The Kinetics of the Austenite-Ferrite Phase Transformation of Fe-4Cr Alloy during Continuous Cooling

2011 ◽  
Vol 194-196 ◽  
pp. 1203-1209
Author(s):  
Li Fang Zhang ◽  
Dan Tian Zhang ◽  
Ze Sheng Yan ◽  
Yong Chang Liu
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Phase Transformation ◽  
Room Temperature ◽  
Interfacial Structure ◽  
Transformation Model ◽  
Transformation Time ◽  
The Matrix ◽  
Kinetics Of ◽  
Time Decrease

The massive transformation, austenite (γ) → ferrite (α), in Fe-4Cr alloy subjected to cooling from the high-temperature austenite down to room temperature at cooling rates of 75, 150, 330 K min-1 were experimentally investigated by means of high-resolution differential dilatometry. It is found that the onset transformation temperature and the overall transformation time decrease with increasing the cooling rate applied. Furthermore, by fitting the calculated transformed fraction according to developed phase-transformation model to the experimental data obtained by differential dilatometry, the kinetic parameters are obtained which show the activation energy for growth and the activation energy for nucleation are considerably different, this may be due to considerably different interfacial structure with the matrix for minute embryos and for the much larger growing particles.

Ferrite Transformation Kinetics of Severely Hot-Deformed Austenite

2012 ◽  
Vol 706-709 ◽  
pp. 1562-1567 ◽  
Author(s):  
Akira Yanagida ◽  
J. Jin Shan Liu ◽  
Jun Yanagimoto
Keyword(s):  
Phase Transformation ◽  
Volume Fraction ◽  
Testing Machine ◽  
Dislocation Cell ◽  
Plain Carbon Steel ◽  
Transformation Kinetics ◽  
Ferrite Transformation ◽  
Short Time ◽  
Ferrite Nucleation ◽  
Kinetics Of

The ferrite transformation kinetics of severely hot-deformed austenite has been studiedby considering ferrite nucleation from dislocation cell blocks inside austenite grains. The size ofdislocation cell blocks and ferrite grain size just after phase transformation are acknowledged to beinversely proportional to the square root of dislocation density. It is found that the ferrite nucleationrate in this area can reach the saturated state at a high temperature just under Ae3, and the ferritetransformation finishes within a very short time. The kinetics of ferrite volume fraction and theferrite grain growth after phase transformation for plain carbon (0.1%C, 0.2%Si, 1.0%Mn) steelhave been studied using a THERMECMASTER hot-compression testing machine. These modelscan be applied to the hot and warm forming processes of plain carbon steel to predict the ferritetransformation from severely deformed austenite.

scholarly journals Effect of Cold Rolling on the Phase Transformation Kinetics of an Al0.5CoCrFeNi High-Entropy Alloy

Entropy ◽  
2018 ◽  
Vol 20 (12) ◽  
pp. 917 ◽  
Author(s):  
Jun Wang ◽  
Haoxue Yang ◽  
Tong Guo ◽  
Jiaxiang Wang ◽  
William Yi Wang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Expansion ◽  
Phase Transformation ◽  
Cold Rolling ◽  
High Entropy Alloy ◽  
Transformation Rate ◽  
Transformation Kinetics ◽  
High Entropy ◽  
Phase Transformation Kinetics ◽  
Kinetics Of

The solid state phase transformation kinetics of as-cast and cold rolling deformed Al0.5CoCrFeNi high-entropy alloys have been investigated by the thermal expansion method. The phase transformed volume fractions are determined from the thermal expansion curve using the lever rule method, and the deformed sample exhibits a much higher transformation rate. Two kinetic parameters, activation energy (E) and kinetic exponent (n) are determined using Kissinger– Akahira–Sunose (KAS) and Johnson–Mehl–Avrami (JMA) method, respectively. Results show that a pre-deformed sample shows a much lower activation energy and higher kinetic exponent compared with the as-cast sample, which are interpreted based on the deformation induced defects that can promote the nucleation and growth process during phase transformation.

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