Experimental Investigation on the Deformation Behaviour and Curve Prediction Method of 7075 Aluminum Alloy

In this study, uniaxial tensile and creep tests were performed to describe the low- and intermediate-temperature deformation behaviour of the 7075 Aluminum (Al) alloy. Hollomon model was proven to be a feasible choice for obtaining the true stress-strain curve of the material in practical engineering. Meanwhile, the influence of strain rate was also estimated by Johnson-Cook (JC) model. The elastic-plastic deformation behaviour was reasonably predicted based on the machine learning method. In addition, creep deformation and damage evolution were estimated using the Kachanov-Robotnov (K-R) creep damage model. The steady-state creep stage was found to account for approximately 40% of the creep life. Based on these, isochronous stress-strain curves of the 7075 Al alloy were established, considering the influence of elastic-plastic and creep deformation features. Three limit strain criteria were used to estimate the allowable stress for different lifetimes, which may provide a reference for practical engineering structures.