Flow stress of high-strength weldable 2195 aluminium-lithium alloy during hot compression deformation

By isothermal compression test at Gleeble-1500 thermal-mechanical simulator, the flow stress behavior of 2195 aluminium-lithium alloy during hot compression deformation was studied with the strain rate rang from (0.001)s~(-1)to 10 s~(-1)and the temperature range from 360 ℃ to 520 ℃. The physical essence of hot deformation for 2195 alloy was also studied. The results show that when the strain rate is 1 s~(-1)(the deformation temperature is 520 ℃) and (0.001,) 0.01 and 0.1 s~(-1)(360520 ℃), the flow stress decreases after a peak value, showing continuous dynamic recrystallization. The steady-state flow characteristics exist on the other deformation conditions. The flow stress of 2195 alloy during high temperature deformation can be expressed by a Zener-Hollomon parameter in the hyperbolic sine function. The values of A, α and n in the analytical expressions of flow stress(σ) are fitted to be 2.569×10~(17)s~(-1), 0.012 48 MPa~(-1)and 5.94. The hot deformation activation energy of 2195 alloy during hot deformation is 250.45 kJ/mol.