Constitutive Model and Processing Maps of 7055 Aluminum Alloy Used for Fasteners

Abstract

The hot deformation behavior of an annealed 7055 aluminum alloy was investigated by isothermal compression tests over the temperatures range of 250-450 °C and strain rates range of 0.001-10 s -1 . The true stress-strain curves were obtained by applying friction and temperature corrections to experimental data. Based on the corrected curves, a sixth-order polynomial Arrhenius-type constitutive equation is established to represent the material characteristic constants. To investigate the workability of this material, processing maps representing the power dissipation capacity with examining various strains were created. According to the processing maps and examination of microstructures, the recommended processing parameters were within the temperatures range of 300-400 ℃ and strain rates range of 10-1.5-1 s -1 , a good workability and uniformly deformed grains can be obtained under this condition. The preponderant softening mechanism is DRV (dynamic recovery) over all the recommended deformation parameter domains, but the effect of DRX (dynamic recrystallization) is enhanced in regions of low strain rate and high temperature deformation.

Keywords: 7055 aluminum alloy, Constitutive model, Hot deformation behavior, Processing map, Microstructural, Dynamic recovery