Aluminum profiles have high plasticity and low resistance at high temperatures, and coupled with intensified atomic diffusion processes, complete recrystallization occurs, which is beneficial for the improvement of the structure. Under the condition where triaxial compressive stress is dominant, hot deformation can most effectively change the as-cast structure of aluminum profiles. By applying an appropriate amount of deformation, the as-cast structure can undergo the following favorable changes.
(1) General thermal deformation is accomplished through multiple passes of repeated deformation. Since hardening and softening processes occur simultaneously in each pass, the deformation of industrial aluminum profiles breaks the coarse columnar grains. At the same time, it can also help heal some tiny cracks.
(2) Due to the effect of hydrostatic pressure in the stress state, it can promote the welding of bubbles present in the cast structure, compaction of shrinkage cavities, densification of looseness, turning it into a relatively dense structural organization.
(3) Due to the enhanced atomic thermal motion capability at high temperature, under the action of stress, with the aid of atomic free diffusion and interdiffusion, it is conducive to relatively reducing the inhomogeneity of the chemical composition in the ingot.
Through hot deformation, the ingot structure is improved into a deformed structure, giving it higher density, uniform fine equiaxed grains, and relatively uniform chemical composition, thereby significantly enhancing both plasticity and strength indicators.
