In this study, large-sized Al–Zn–Mg–Cu alloy billets were prepared by direct chill casting imposed with annular electromagnetic stirring and intercooling; a process named uniform direct chill casting. The effects of uniform direct chill casting on grain size and the alloying element distribution of the billets were investigated and compared with those of the normal direct chill casting method. The results show that the microstructures were refined and the homogeneity of the alloying elements distribution was greatly improved by imposing the annular electromagnetic stirring and intercooling. In uniform direct chill casting, explosive nucleation can be triggered, originating from the mold wall and dendrite fragments for grain refinement. The effects of electromagnetic stirring on macrosegregation are discussed with consideration of the centrifugal force that drives the movement of melt from the central part towards the upper-periphery part, which could suppress the macrosegregation of alloying elements. The refined grain can reduce the permeability of the melt in the mushy zone that can restrain macrosegregation.

To meet the lightweight demands of automobiles, Al composite sheets require excellent mechanical properties under the condition of minimal thickness after high-temperature brazing processing. Generally, the standard used Al brazing sheets have a low strength before and after brazing. To overcome this issue, this work develops a novel 4343/3003/6111/3003 four-layer Al clad sheet, whose microstructure and mechanical properties are systematically investigated. The results show the observable fibrous microstructure with elongated grains parallel to the rolling direction in the developed four-layer Al clad sheet of the cold-rolled and annealed states. After brazing, this fibrous microstructure transforms into coarse equiaxed grains. In addition, the 4343 layer is the brazing layer. Si is mainly distributed in the 4343 layer of the cold-rolled Al clad sheets, whereas Si penetrates into the core layer along the grain boundaries after brazing. The cold-rolled samples present a certain brittleness from fracture morphology, whereas the final annealed ones show a typical ductile fracture. Meanwhile, the typical intergranular fracture is visible after brazing. The mechanical properties of the Al clad sheets are improved after brazing, with an increase of 76% in tensile strength and 62% in yield strength, compared with the final annealed ones. The elongation is increased by 29% compared with that of the cold-rolled ones. This study provides a theoretical basis for further improvement of the strength of aluminum honeycomb panels.

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.