Dynamic recrystallization behavior during hot deformation of as-cast 4Cr5MoSiV1 steel

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


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.


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