Fig. 1 Schematic of annealing heat treatment used for generation of two different grain sizes of specimens and thermo-mechanical conditions of hot compression test after annealing

Fig. 2 Microstructures of annealed copper with different cooling methods of a air-cooled (with an average grain size of 50 μm), b furnace cooled (with an average grain size of 20 μm) copper

Fig. 3 True stress-strain curves of pure copper at various strain rates, IGS, and deformation temperatures of a 673 K, b 773 K, c 873 K, d 973 K, e 1073 K

Fig. 4 Influences of IGS and Zener-Hollman (Z) parameter (strain rate and temperature) on the dominant deformation mechanism and flow stress behavior of pure copper

Fig. 5 Curves of $\sigma$ - $\varepsilon$ and $\theta$ - $\sigma$ at 973 K and 0.001 ${\text{s}}^{ - 1}$ for IGS of 50 μm

Fig. 6 Work hardening rate $theta$) changes at different temperatures and IGS with strain rates of a 0.001 s-1, b 0.01 s-1, c 0.1 s-1

Fig. 7 Critical a stress, b strain at different temperatures, strain rates, and IGS of 20 µm (F) and 50 µm (L)

Fig. 8 Relationship between the peak and critical values of a strain, b stress and Z for IGS of 20 μm

Fig. 9 Relationship between the peak and critical values of a strain, b stress and Z for IGS of 50 μm

Fig. 10 Correlation between the experimental and predicted peak and critical values of a strain, b stress for IGS of 20 μm

Fig. 11 Correlation between the experimental and predicted peak and critical values of a strain, b stress for IGS of 50 μm

Fig. 12 Microstructures of hot deformed samples with IGS of 20 μm at different temperatures and strain rates at the true strain of 0.6

Fig. 13 Microstructures of hot deformed samples with IGS of 50 μm at different temperatures and strain rates at the true strain of 0.6

Fig. 14 Microstructures of the central part of the deformed sample at 673 K and 0.001 ${\text{s}}^{ - 1}$ and the strain of 0.6 with IGS a 20 μm and b 50 μm

Fig. 15 Microstructures of the hot deformed samples with IGS of a 20 μm, b 50 μm at 1073 K and 0.001 ${\text{s}}^{ - 1}$ and samples with IGS of c 20 μm and d 50 μm at 773 K and 0.001 ${\text{s}}^{ - 1}$

Fig. 16 Evaluation of average grain size and grain growth rate with various temperatures and strain rates

Fig. 17 Microstructures of the deformed samples with IGS of a 20 μm, b 50 μm at 973 K and 0.1 ${\text{s}}^{ - 1}$ and samples with IGS of c 20 μm and d 50 μm at 973 K and 0.001 ${\text{s}}^{ - 1}$

Fig. 18 Evaluation of average grain size at various temperatures and strain rates

Fig. 19 Relationship between $\ln \left\{ {\ln \left[ {1/\left( {1 - X_{{{\text{DRX}}}} } \right)} \right]} \right\}$ and $\ln \left[ {\left( {\varepsilon - \varepsilon_{{\text{c}}} } \right)/\varepsilon_{{\text{p}}} } \right]$ at different strain rates and temperatures for determination slope n and intercept k for IGS of a 20, b 50 μm

Fig. 20 Volume fraction of DRX as a function of strain at different strain rates and deformation temperatures of a 673 K, b 773 K, c 873 K, d 973 K, e 1073 K

Fig. 21 Microstructures of hot deformed samples with IGS of a 20 μm, b 50 μm at 973 K, 0.01 ${\text{s}}^{ - 1}$ and true strain of 0.17

Fig. 22 Microstructures of hot deformed samples with IGS of a 20 μm, b 50 μm at 1073 K, 0.1 ${\text{s}}^{ - 1}$ and true strain of 0.17