Microstructural evolution characteristics and a unified dislocation-density related constitutive model for a 7046 aluminum alloy during hot tensile

Abstract

Hot tensile features of a commercial 7046 aluminum alloy are investigated through employing high-temperature tensile tests. The evolving mechanisms of microstructures over high-temperature tensile parameters are systematically revealed. A unified dislocation-density related constitutive model is proposed to reconstruct hot tensile stress–strain behaviors. Results imply that the microstructural evolving features are acutely influenced by tensile parameters. The principal softening mechanism converts from dynamic recovery (DRV) to dynamic recrystallization (DRX), as the tensile temperature reaches 350 °C or above. The combined DRX nucleation features containing discontinuous DRX (DDRX) as well as continuous DRX (CDRX) together emerge. Furthermore, the CDRX behavior characterized by substructural nucleation and interaction becomes apparent at low tensile temperature or high strain rate, while the DDRX process is weaken. Through validation, the reproduced tensile stress, grain size as well as DRX fraction are good accordance with experimented values, which proves the proposed dislocation-density related equation can enjoy an outstanding reproduced capacity for the thermal tensile features of a 7046 aluminum alloy.

Keywords

• Hot deformation
• Dynamic recrystallization
• Dislocation density
• Constitutive model
• 7046 aluminum alloy