Dynamic Recrystallization Behavior of 7056 Aluminum Alloys during Hot Deformation

Abstract

To investigate the dynamic recrystallization behavior of 7xxx aluminum alloys, the isothermal compression tests were carried on the 7056 aluminum alloy in the temperatures range of 320–440 °C and in the strain rates range of 0.001–1 s⁻¹. In addition, the microstructure of samples were observed via electron back scanning diffraction microscope. According to the results, true stress and true strain curves were established and an Arrhenius-type equation was established, showing the flow stress increases with the temperature decreasing and the strain rate increasing. The critical strain (ε _c) and the critical stress (σ _c) of the onset of dynamic recrystallization were identified via the strain hardening rate and constructed relationship between deformation parameters as follows: ε _c=6.71×10⁻⁴ Z ^{0.137 3} and σ _p=1.202σ _c+12.691. The DRX is incomplete in this alloy, whose volume fraction is only 20% even if the strain reaches 0.9. Through this study, the flow stress behavior and DRX behavior of 7056 aluminum alloys are deeply understood, which gives benefit to control the hot working process.

Keywords

Al-Zn-Mg-Cu alloys / flow stress behavior / dynamic recrystallization / hot deformation

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