Intrinsic Equations and High-Temperature Heat Distortion Behavior of TA4 Alloy

In this study, the high-temperature thermal deformation behavior of TA4 alloy was investigated through thermal compression experiments. The effects of deformation temperature and strain rate on rheological stress were analyzed by examining the variations in stress-strain curves under different conditions and establishing a constitutive equation based on the dynamic material theory model. The prediction accuracy of the developed constitutive model was evaluated, yielding a correlation coefficient of 0.9612 between predicted and experimental values, an average absolute percentage error of 8.7210%, and an average root mean square error of 11.0635 MPa. Thermal processing diagrams were established and plotted to analyze the optimal processing zone and the destabilization zone under different strains. The optimal processing zones at different strains are obtained from the thermal processing diagrams, which are 1040~1133K, 0.01~0.7s-1 at a strain of 0.9, 940~1000K, 0.01~0.04 s-1 at a strain of 0.6, 940~1000K, 0.01~0.08s-1 at a strain of 0.3, 940~1000K, 0.01~0.08s-1 at a strain of 0.3. Additionally, the thermal deformation mechanisms of TA4 alloy under varying deformation parameters were analyzed using EBSD characterization. The results indicate that the primary deformation softening mechanisms include dynamic recovery (DRV) at low temperatures and high strain rates, dynamic recrystallization (DRX) at high temperatures and high strain rates, and DRX at low strain rates.