Hot deformation behavior and microstructure of AA2195 alloy under plane strain compression.

The hot deformation behavior of Al-Cu-Li alloy was studied under plane strain compression in the temperature range of 400–500 °C and strain rate of 0.01–10 s − 1 . The related microstructure was studied by optical microscopy, electron back-scattered diffraction and transmission electron microscope. The results showed that the stress decreased significantly with the increase of temperature and decrease of strain rate. However, stress increase was found after peak stress at strain rate of 0.01 s − 1 and deformation temperature 440–500 °C. Constitutive equation based on the hyperbolic sine equation was established and the apparent activation energy of plane strain compression was estimated to be 226.7 KJ/mol. Precipitates decreased and finally disappeared with decreasing Z value, having an impact on the softening mechanism. Plate-shaped particles and precipitate zones restrained the proceeding of dynamic recovery but increased store energy for discontinuous dynamically recrystallization nuclei. Therefore, recrystallization nuclei more obviously occurred in the sample with higher ln Z value than the one with lower ln Z value at close ln Z value. The microstructure of all deformed specimens was composed of elongated grains and new quasi-equiaxed grains. However, the basic deformation mechanism was dynamic recovery. The mechanism of recrystallization nuclei transformed discontinuous dynamic recrystallization into continuous dynamic recrystallization with the decreasing Z values. [ABSTRACT FROM AUTHOR]