Flow Behavior and Dynamic Recrystallization of BT25y Titanium Alloy During Hot Deformation

2018 ◽  
Vol 37 (2) ◽  
pp. 181-192 ◽  
Author(s):  
Xuemei Yang ◽  
Hongzhen Guo ◽  
Zekun Yao ◽  
Shichong Yuan

AbstractThe high-temperature plastic deformation and dynamic recrystallization behavior of BT25y alloy were investigated within the deformation temperatures of 1,213–1,293 K and strain rates of 0.001–1.0 s–1 on a Gleeble-1500 thermo-mechanical simulator. Results showed that the dynamic recrystallization (DRX) mechanism played an important role in the hot deformation of BT25y alloy. Based on the regression analysis of the true stress–strain data, the stress exponent and deformation activation energy of BT25y alloy were calculated to be 3.4912 and 288.0435 kJ/mol, respectively. The θ-σ and dθ/dσ–σ curves were plotted to further obtain the critical stress and critical strain for the occurrence of DRX. Based on the analysis results, the DRX kinetic model was established. The model was validated by the comparison between predicted and experimental volume fraction of DRX. As the DRX evolution was sensitive to deformation temperature and strain rate, quantities of dynamically recrystallized grains appeared at higher temperatures and lower strain rates.

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1341
Author(s):  
Hai-long Yi ◽  
Daixiu Wei ◽  
Yingchen Wang ◽  
Liqiang Wang ◽  
Ming-yang Fang ◽  
...  

The CoCrNi and precipitate-hardened (CoCrNi)94Ti3Al3 medium entropy alloys (MEAs) have attracted much attention, due to their exceptional mechanical properties, whereas the hot deformation characteristics have not been revealed. In the present study, we investigated the dynamic recrystallization behavior and microstructure evolutions of the two MEAs hot-compressed at single-phase temperatures. The constitutive equation was obtained, and microstructures were observed. Discontinuous dynamic recrystallization acted as a key mechanism of grain refinement at a relatively higher temperature and lower strain rate, which leads to the formation of a homogeneous grain structure. The addition of Ti and Al promoted dynamic recrystallization due to the solid solution hardening effect. The results provide valuable guidelines for microstructure refinement via thermomechanical processing.


2021 ◽  
Vol 56 (14) ◽  
pp. 8762-8777
Author(s):  
Yahui Han ◽  
Changsheng Li ◽  
Jinyi Ren ◽  
Chunlin Qiu ◽  
Shuaishuai Chen ◽  
...  

2013 ◽  
Vol 275-277 ◽  
pp. 1833-1837
Author(s):  
Ke Lu Wang ◽  
Shi Qiang Lu ◽  
Xin Li ◽  
Xian Juan Dong

A Johnson-Mehl-Avrami-Kolmogorov (JMAK)-model was established for dynamic recrystallization in hot deformation process of 52100 steel. The effects of hot deformation temperature, true strain and strain rate on the microstructural evolution of the steel were physically studied by using Gleeble-1500 thermo-mechanical simulator and the experimental results were used for validation of the JMAK-model. Through simulation and experiment, it is found that the predicted results of DRX volume fraction, DRX grain size and average grain size are in good agreement with the experimental ones.


2020 ◽  
Vol 321 ◽  
pp. 12008
Author(s):  
Y.Y. Luo ◽  
X.N. Mao ◽  
H.Y. Yang ◽  
Y.F. Yin ◽  
Z.Z. Zhao ◽  
...  

The dynamic recrystallization behavior of as-cast Ti-46.5Al-3Ta-2Cr-0.2W alloy during isothermal compression process with nominal deformation of 50% and strain rates from 0.01s to 1s was investigated by electron microscopy. The results showed that the deformation mechanism of this alloy can be concluded as grain boundary sliding and mechanical twins, which induce the final dynamic recrystallization. The phase boundary bulging was found to be the major nucleation mechanism responsible for the lamellar globularization and the formation of recrystallized γ grains inside the lamellar colony under the high strain rate. The recrystallized γ grains induced by the twinning is the main mechanism for refining α2 lamellar microstructures under low strain rate.


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