A hot compression test was conducted across a range of temperatures (350, 400, 450, and 500 °C) and varying strain rates (0.001–10 s−1) to explore the hot compression behavior of the 6063 alloy. Hot processing maps were obtained based on the stress–strain curves. Optimal processing parameters were identified as residing within the intervals of (470–500 °C, 0.01–0.1108 s−1), achieving a maximum dissipation efficiency of 0.4, which is of great importance for perfecting hot processing. The microstructure evolution was characterized using an optical microscope and a transmission electron microscope. The initial grains were elongated under compressive deformation, and the density of dislocation rose with increasing strain rate and decreasing temperature. Dynamic recovery serves as the main dynamic softening mechanism during hot compression.
In the current manuscript, the hot deformation behavior and the thermal processing map of 6082-T6 rolled aluminum alloy sheet were studied. A series of compression tests were conducted using the Gleeble-3500 thermal simulation machine under the conditions of 200–350 °C and 0.001–1 s−1. In order to tackle the stress errors caused by friction and plastic deformation temperature rise, the friction correction model and the adiabatic temperature rise interpolation method were used, respectively, to correct the flow stress curve. Based on the corrected data, a strain-compensated Arrhenius constitutive equation was constructed. Through the 4th-order polynomial fitting of material parameters and strain, the measured and predicted stresses were compared, with the average relative error reaching 10.50%. The thermal processing map was drawn based on the dynamic material model, and the material instability region was concentrated in the low-temperature high-strain rate zone. Within the investigated temperature and strain rate range, the optimal processing window was 320–350 °C and 0.001–0.031 s−1. Combined with microscopic characterization by Optical microscope and transmission electron microscope, it was found that deformation at low temperature and high strain rate was mainly dynamic recovery, and dynamic recrystallization could fully occur at high-temperature low-strain rate. The research results can provide theoretical support for the optimization of the hot forging and hot stamping processes of this alloy.
In this study, a novel casting–forging hybrid forming technique, introducing torsional shear during squeeze casting, was investigated. This approach enhances the forming efficiency and refines the grain size. Using a finite element method coupled with a viscoplastic self-consistent model, a macro-microscopic simulation model of the squeeze casting torsional forming process was established. The introduction of torsional shear in SQ results in a more uniform distribution and lower equivalent stress, thereby improving the forming efficiency. Additionally, the shear force is increased during the forming process, the shear force is greater with the distance from the torsional axis increasing, and the great shear force could be maintained for a long time. Ultimately, this leads to a thinner wall thickness, finer secondary dendrites, and eutectic Si in the workpiece. During the SQT process, for introducing slip during the late stage of deformation, a significant shift in grain rotation directions happens and the grain rotation angles increase, finally attributed to the development of the texture.