Characterization and constitutive analysis-based crystal plasticity of warm flow and fracture behaviours of 2060 Al–Cu–Li alloy

Abstract

AA2060-T8 is a relatively new Al–Cu–Li alloy developed in the last few years as a lightweight alternative to conventional Al alloys. Thus, it is essential to characterize the warm flow, fracture, and anisotropic behaviours of this alloy and propose constitutive analysis-based crystal plasticity (CP) modelling to link its mechanical behaviour with the microstructural state. Therefore, in this study, isothermal warm tensile tests were conducted using a Gleeble-3800 thermomechanical simulator and different sample orientations at temperatures and strain rates varying from 373 to 573 K and 0.001–0.1 s−1, respectively. The tensile behaviour of the 2060 Al–Cu–Li alloy sheet depends on the sample orientations, which results in significant anisotropy. The anisotropic degree of the tensile properties of this alloy was significantly reduced by increasing the forming temperature above 473 K. In addition, the fracture behaviours of 2060 Al–Cu–Li sheets were transformed from mixed ductile-brittle fracture mode to ductile fracture mode by decreasing strain rates and increasing the temperatures, respectively. Afterward, a novel crystal plasticity model was proposed to describe the grain behaviour and the deformation mechanism of 2060 Al–Cu–Li alloy under warm forming conditions. The developed constitutive model was implemented using the monolithic time-integration algorithm-based backward Euler method. The results acquired from the proposed constitutive analysis agree well with those obtained from experimentation in all testing conditions. This indicates its ability to accurately predict the warm flow behaviour of 2060 Al–Cu–Li alloy under different strain rates and loading directions.

Keywords

• 2060 Al–Cu–Li alloy
• Constitutive analysis
• Fracture mechanisms
• Crystal plasticity modelling
• Storage and recovery processes
• Friedel-escaig model