Flow behavior and dynamic recrystallization mechanism of A5083 aluminum alloys with different initial microstructures during hot compression

摘要

Hot compression tests of A5083 aluminum alloys with extruded and homogenized initial microstructures were carried out at varying temperatures (350 to 450 °C) and strain rates (0.1 to 10/s). The effects owing to nonuniform temperature and strain distributions caused by deformation were compensated by inverse analysis to determine the flow curves. The obtained flow curves with a homogenized initial microstructure were lower than those with an extruded initial microstructure. Constitutive descriptions were obtained to study the dynamic kinetics during compression, and comparisons between the predicted results from constitutive equations and the experimental results from associate microstructures verified their accuracy. Electron backscatter diffraction (EBSD) was utilized for observing microstructures. The characteristics of continuous dynamic recrystallization, particle-stimulated dynamic recrystallization and conventional dynamic recrystallization were confirmed. The dynamic recrystallization process with a homogenized initial microstructure is slower than that with an extruded initial microstructure, owing to the different amounts of subgrain structures during the initial deformation stage, which can affect the speed of the continuous dynamic recrystallization process. Microhardness tests were conducted to study the connection between microstructure and mechanical property. The microhardness after deformation with an extruded initial microstructure are higher than those with a homogenized initial microstructure.