Thermo-mechanical finite element simulation and experimental study on a warm caliber rolling TA2 alloy: Deformation behavior, microstructure and mechanical properties

A novel severe plastic deformation (SPD) process is developed to fabricate ultrafine-grained (UFG) TA2 alloy via multi-pass warm caliber rolling, at four temperatures (500, 550, 600, and 650 °C), achieving a total height reduction. A thermo-mechanically coupled finite element (FE) simulation revealed a heterogeneous strain distribution characterized by a fan shaped high shear zone and a core low strain zone distributions consistent with electron backscatter diffraction (EBSD) characterization. It is revealed the dominant deformation mechanism transitions from twinning (primarily T1 tensile twins) to dislocation slip and thermally activated dynamic recrystallization (DRX) as the temperature increases. This transition significantly weakens the fiber texture (Max intensity = 14.95 to 3.95) while introducing recrystallization texture components. Compared to higher temperature conditions dominated by extensive DRX, rolling at 500 °C effectively preserves maximizing tensile strength (UTS = 868 MPa) while maintaining acceptable ductility (Elongation = 8.9%). When ductility is prioritized, the temperature range of 600 ∼ 650 °C is more optimal.