Hot Deformation Behaviors and Microstructural Evolution of Mo-42Re Alloy Prepared by Electron Beam Melting

The hot deformation behavior and microstructure evolution of electron beam-melted Mo-42Re alloy were studied by hot compression tests at 1200 ~ 1500 °C and 0.001 ~ 1 s⁻¹. Based on the experimental results, a constitutive model was developed to predict the flow stress and the average absolute relative error, and the Pearson correlation coefficient of the model was 3.75% and 0.98, respectively. The microstructure after deformation was characterized using electron back scatter diffraction (EBSD) and transmission electron microscope (TEM) techniques. The microstructural analysis results showed that dynamic recovery (DRV) was the dominant mechanism during hot deformation in the selected temperature range, with only partial dynamic recrystallization (DRX) occurring. The temperature for complete DRX should be above 1500 °C. At low temperature (1200 °C) and high strain rate (1 s⁻¹), the sub-grain nucleation was identified as the dominant mechanism for DRX. At elevated temperature (1500 °C) and low strain rates (0.001 s⁻¹), grain boundary bulging was observed to be the primary nucleation mechanism. Recrystallized grains were more likely to form at deformed grain boundaries. During deformation at high temperatures or low strain rates, the larger strain accumulation at grain boundaries was more readily released, facilitating the formation of recrystallized grains.