Influence of thermo-mechanical conditions on the microstructure and mechanical property of spray-formed 7055 aluminum alloy

A series of isothermal compression experiments under a deformation temperature ranging from 380 degrees C to 440 degrees C and strain rates ranging from 0.1 s(-1) to 15 s(-1) were carried out to investigate the flow behavior of a spray-formed 7055 aluminum alloy. The microstructural morphology, chemical composition and orientation characteristics were examined by optical microscopy (OM) and scanning electron microscope (SEM) combined with energy dispersive spectroscopy (EDS) detection and electron back scattered diffraction (EBSD) technology. The results show that the dynamic softening mechanisms were profoundly affected by different thermo-mechanical conditions and the deformation stage, which caused a complicated material flow behavior with the related microstructure development and texture evolution. A partially dynamic recrystallized behavior was observed, which occupied a relatively small volume fraction of the total deformed microstructure under current deformation conditions. The relationship between the different mechanisms for dynamic recrystallization (DRX) and the hot deformation conditions was discussed and confirmed through crystal orientation research. The changes in chemical composition and morphology of second phases were studied and their existing forms, with corresponding impacts on microstructure under different hot deformation conditions, were analyzed. The microhardness tests of the deformed matrix were implemented to reveal the material strengthening mechanism. This work contributes to the comprehensive understanding of the high temperature flow behavior, microstructural characteristic and mechanical properties of spray-formed 7055 aluminum alloy, which provides theoretical support for related research and potential industrial applications.