Fig. 1 Stress-strain curves of experimental steels at different temperatures and strain rates

Fig. 2 Strain hardening rate (θ) versus flow stress (σ) at strain rate of 0.1 s-1 and different deformation temperatures: a V1 steel; b V2 steel; c V3 steel

Fig. 3 - (dθ/dσ)-σ curves at strain rate of 0.1 s-1 and different temperatures: a V1 steel; b V2 steel; c V3 steel

Fig. 4 Relationship between critical DRX parameters and deformation temperatures at strain rate of 0.01 s-1: a peak stress; b critical stress; c peak strain; d critical strain

Fig. 5 Variation in residual sum of squares (RSS) of n with the value of α for V1 steel

Fig. 6 Relationship among strain rate, deformation temperature and peak stress for V1 steel: a ln[sinh(ασp)]-\(\ln \dot{\varepsilon }\); b ln[sinh(ασp)]-104/T

Fig. 7 Relationship between Z and \(\ln [\sinh (\alpha \sigma_{\text{p}} )]\) for V1 steel

Fig. 8 Optical microstructures of V1 and V3 steels deformed at 950 °C, 0.01 s-1: a V1 steel; b V3 steel

Fig. 9 TEM micrograph and EDX analysis of precipitates in V3 steel: a morphology of precipitates; b EDX analysis result of precipitate

Fig. 10 Relationship between characteristic points: aσp and σc; bεp and εc

Fig. 11 Relationship between $\ln [\ln (1/(1 - X))]$ and $\ln [(\varepsilon - \varepsilon_{\text{c}} )/\varepsilon_{\text{p}} )]$ under different deformation conditions: a V1 steel; b V2 steel; c V3 steel

Fig. 12 DRX volume fraction at strain rate of 0.01 s-1 and different deformation temperatures for V1 steel a; kinetics of DRX for three experiment steels under the same deformation condition (950 °C, 0.1 s-1) b

Fig. 13 Optical microstructures of three experimental steels deformed at 950 °C, 0.1 s-1: a V1 steel; b V2 steel; c V3 steel