Microstructure evolution and activation energy during superplastic deformation of FeAl based intermetallics

1997 ◽  
Vol 36 (11) ◽  
pp. 1289-1294 ◽  
Author(s):  
Dingqiang Li ◽  
Dongliang Lin (T.L. Lin)
Keyword(s):  
Activation Energy ◽  
Microstructure Evolution ◽  
Superplastic Deformation

scholarly journals Liquid Phase Assisted Superplastic Deformation of TiO2-Doped ZTA Ceramics

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2050 ◽  
Author(s):  
Yufei Zu ◽  
Guoqing Chen ◽  
Xuesong Fu ◽  
Wenlong Zhou
Keyword(s):  
Activation Energy ◽  
Liquid Phase ◽  
Grain Boundary ◽  
Microstructure Evolution ◽  
Deformation Behavior ◽  
Superplastic Deformation ◽  
Q Value ◽  
Deformation Activation Energy ◽  
Zirconia Toughened Alumina ◽  
Q Values

In this study, the compressive deformation of zirconia toughened alumina (ZTA) ceramics doped with different amounts of TiO2 dopants were investigated in the temperature range of 1300–1400 °C to evaluate the stress exponent (n value) and apparent deformation activation energy (Q value). With 0–8 wt.% TiO2 dopants, the n values and Q values of the TiO2-doped ZTA ceramics were calculated as 2–3 and 605–749 kJ/mol, respectively. Moreover, three grain boundary features were observed in these deformed materials, named the clean grain boundary, thin liquid phase grain boundary, and thick liquid phase grain boundary. Based on the deformation behavior and microstructure evolution, it was found that the lower apparent activation energy and higher strain rate of TiO2-doped ZTA ceramics are intensively related to the grain boundary feature.

Research on Temperature Changes and Microstructure Evolution of Steel Target after the Penetration by Copper Jet

2011 ◽  
Vol 311-313 ◽  
pp. 953-956
Author(s):  
Hao Chen ◽  
Gang Tao
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Temperature Distribution ◽  
Microstructure Evolution ◽  
Deformation Zone ◽  
Superplastic Deformation ◽  
Theoretical Formula ◽  
Temperature Changes ◽  
Normal Deformation ◽  
Steel Target

In order to study dynamic response of metal, this paper makes use of theoretical formula to investigate changes of temperature and grain size on steel target after the penetration of copper jet based on data gathered from the experiments. Deformed target penetrated by copper jet could be divided into superplastic deformation zone and normal deformation zone according to the different microstructure. Temperature distribution of each deformation zones is in turn calculated by two constitutive equations. The results indicate that areas with high temperature concentrate on the narrow zone near the penetrated channel. Then, the calculation of grain size conforms to the observation. It is obviously proven that the method used in this paper is trustworthy for calculating the changes of temperature and grain size of target caused by penetration.

scholarly journals Isochronal Phase Transformation in Bimodal Ti-55531

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 790 ◽  
Author(s):  
Fuwen Chen ◽  
Guanglong Xu ◽  
Kechao Zhou ◽  
Hui Chang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Activation Energy ◽  
Phase Transformation ◽  
Microstructure Evolution ◽  
Continuous Heating ◽  
Interface Curvature ◽  
The Difference ◽  
Treatment Procedures ◽  
And Control

Bimodal microstructures where globular α and acicular α phases are embedded in the β matrix are commonly used in industry-relevant Ti-55531. To optimize the performance of Ti-55531 through heat treatment, it is crucial to understand and control the phase transformation in the as-received bimodal Ti-55531 as well as its microstructure evolution. In this work, the isochronal phase transformations and microstructure evolution in the bimodal Ti-55531 during the continuous heating were systematically studied by combining dilatometry, XRD phase analyses, and SEM observation. The β → α transformation occurred at 678 K only with the acicular α. When the temperature was higher than 788 K, α → β transformation took place in two separate stages (i.e., αacicular → β and αglobular → β transformation). The dissolution of αglobular occurred after the dissolution of αacicular was completed. Due to the difference in the chemical composition and interface curvature between αacicular and αglobular, the average activation energy for αacicular → β transformation was lower than that for the αglobular → β transformation. The isochronal phase transformation and microstructure evolution during continuous heating in the present work could be used to optimize heat treatment procedures for desired mechanical properties.

Effect of the Strain and Strain Rate on Microstructure Evolution and Superplastic Deformation Mechanisms

2019 ◽  
Vol 120 (1) ◽  
pp. 87-94 ◽  
Author(s):  
O. A. Yakovtseva ◽  
A. V. Mikhaylovskaya ◽  
A. D. Kotov ◽  
O. I. Mamzurina ◽  
V. K. Portnoy
Keyword(s):  
Strain Rate ◽  
Microstructure Evolution ◽  
Superplastic Deformation ◽  
Deformation Mechanisms ◽  
Strain And Strain Rate

The Mechanism of Superplastic Deformation with High Activation Energy

1991 ◽  
Vol 66-69 ◽  
pp. 1421-1424
Author(s):  
András Juhász ◽  
P. Tasnádi ◽  
Nguyen Q. Chinh ◽  
I. Kovács
Keyword(s):  
Activation Energy ◽  
Superplastic Deformation ◽  
High Activation ◽  
High Activation Energy

Effect of Silver on Superplastic Deformation in YBa2Cu3O7–x/Ag Composites

2002 ◽  
Vol 17 (5) ◽  
pp. 1172-1177
Author(s):  
Jondo Yun ◽  
Ye T. Chou ◽  
Martin P. Harmer
Keyword(s):  
Activation Energy ◽  
Grain Size ◽  
Superplastic Deformation ◽  
Close Agreement ◽  
Silver Content ◽  
Strain Rates ◽  
Compression Tests ◽  
Fine Grained ◽  
Soft Inclusion ◽  
Activation Energy Of Deformation

Superplastic deformation was studied in fine-grained (0.7–1.1 μm) YBa2Cu3O7–x/Ag composites containing 2.5–25 vol% Ag. The compression tests were conducted in the temperature range of 750–875 °C and at strain rates of 10−5 to 10−3/s. For the YBa2Cu3O7−x/25%Ag composites with grain size of 0.7–1.1 μm, deformed at 800–850 °C and 10−5 to 10−3/s, the stress exponent, grain size exponent, and the activation energy of deformation were 2.0 ± 0.1, 2.5 ± 0.7, and 760 ± 100 kJ/mol, respectively. These values were the same as those of the pure YBa2Cu3O7−x, indicating that the deformation of the composite was controlled by that of the rigid YBa2Cu3O7−x phase. However, the strain rate was increased by the addition of silver as explained by the soft inclusion model of Chen. The dependence of the flow stress on the silver content was in close agreement with the prediction of the model.

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