Modified Constitutive Model of Al-Zn-Mg-Cu-Er Alloy Sheet During High-Temperature Tensile Deformation Process

Rare-earth aluminum alloy materials exhibit excellent strength, plasticity, and toughness at room temperature, making them easily meet the lightweight requirements of structural components, and high-temperature plastic forming is widely applied. Accordingly, the present study is dedicated to investigating the rheological characteristics of rare-earth aluminum alloys subjected to tensile deformation at elevated temperatures. High-temperature tensile tests were implemented across a temperature interval of 623 to 723 K and a strain rate spectrum ranging from 0.01 to 1.0 s−1. Experimental outcomes reveal that the flow stress exhibits a downward trend with the elevation in deformation temperature as well as the reduction in strain rate. It is also confirmed that flow stress correlates closely with the evolution of strain, which further motivates the construction of a modified Arrhenius constitutive equation integrated with strain compensation. Nevertheless, it is noted that the predictive precision of the strain-compensated Arrhenius constitutive model declines remarkably once the applied strain exceeds the scope covered by the experiments. Through error analysis, it was revealed that the material parameters of the Arrhenius-type constitutive model are influenced by strain, strain rate, and deformation temperature. On this basis, an optimized Arrhenius constitutive model was proposed in the current research. The parameter fitting was accomplished by comparing the calculated stresses from the model with experimental data, which involved strain compensation and a comprehensive consideration of the effects of temperature and strain rate. The resulting model is capable of precisely describing the material’s flow behavior within the experimental strain range and effectively predicting it beyond that range.