Thermal Deformation and Grain Control of Extruded Profile for 2196 Al-Li Alloy

Abstract:

Flow behavior and grain structure evolution were studied for 2196 aluminum-lithium alloy during hot compression deformation. Based on extrusion simulation and profile trial production, grain structure control of typical I-shaped thin-walled profiles was achieved. The results show that the alloy exhibits excellent hot deformability in a relatively wide parameter range. The dominate mechanism of microstructure evolution is dynamic recovery, although some localized dynamic recrystallization is also observed. At lower temperatures (350, 400 ℃) and higher strain rates (10 s^-1), strain concentration leads to a small amount of local dynamic recrystallization. Compared to experimental compression deformation, the larger strain of extrusion process promotes the formation of dynamic recrystallization. The differences of deformation conditions on profile section lead to non-homogeneous grain structure. Based on the equipment capability, relatively uniform microstructure be obtained under deformation conditions of 430 ℃ and strain rate of 0.005–0.95 s^-1 on profile section, while maintaining lower fraction of recrystallization and abundant sub-grain structure, which is benefit for the strength and toughness matching.