A New Constitutive Model for 7055 Aluminum Alloy

The hot deformation behavior of spray-formed 7055 aluminum alloy was investigated using a thermo-mechanical simulator by a series of isothermal and constant strain-rate compression tests. These tests were at deformation temperatures ranging from 653 to 713 K and strain rates ranging from 0.1 to 15s(-1). The microstructure characteristics of these deformed samples were examined by optical microscope (OM) and electron back-scattered diffraction (EBSD) techniques. The material flow patterns and relevant microstructural analyses indicated that specific thermo-mechanical conditions including the Zener-Hollomon parameter, temperature, and strain, determined the onset and degree of obvious dynamic recrystallization (DRX) behavior. A partially recrystallized grain microstructure was observed and enhanced the flow softening especially at low Zener-Hollomon values. The influence of different hot deformation conditions on the material flow behavior and the evolution of microstructure was confirmed. A new three-stage constitutive equation, accompanied by a microstructure evolution model, was developed to predict the flow stress of sprayed-formed 7055 aluminum alloy and the corresponding characteristics of DRX transformation during the hot deformation process. The predicted performance was evaluated by experimental data and showed good accuracy.

Automated summary

The hot deformation behavior of spray-formed 7055 aluminum alloy was investigated using a thermo-mechanical simulator through a series of compression tests. Specific thermo-mechanical conditions were found to determine the onset and degree of dynamic recrystallization behavior. A new three-stage constitutive equation and microstructure evolution model accurately predicted the flow stress and DRX characteristics during the hot deformation process.