Effect Of High Pressure Heat Treatment And Rolling Process On The Recrystallization And Recrystallization Texture Of Aluminum Alloys

Aluminum and aluminum alloys have the advantages of low density,high strength to weight ratios,excellent ductility,outstanding corrosion resistance and good formability,and are widely used in industrial sectors such as aviation,aerospace,construction,transportation and chemical industry as well as in daily life.The anisotropy in aluminum alloy sheets can significantly affect the formability and product efficiency of the metal,and it is important to optimize the mechanical properties by regulating the texture formed in the annealing process of aluminum alloy sheets.With the development of high-pressure technology,improving the properties of metallic materials by high-pressure technology has attracted more and more attention.Therefore,it is of great importance to study the effect of highpressure heat treatment on the organization and properties of aluminum alloy sheets.In this paper,high pressure heat treatment was carried out by cold rolling CC 3003,CC 5754 and DC 5052 aluminum alloy sheets with different initial states to different deformations at atmosphere pressure,2 GPa,4 GPa and 6 GPa pressures with annealing temperatures of 482℃(CC 3003)and 537℃(CC 5754 and DC 5052),respectively.The evolution of the texture and the influencing factors during the rolling of aluminum alloys were investigated,the effect of aluminum alloy rolling process on recrystallization and recrystallization texture,the effect of high-pressure heat treatment on recrystallization,recrystallization texture and hardness of aluminum alloys were studied,and the formation mechanism of recrystallization texture of aluminum alloys under high-pressure environment was also elucidated.The evolution of the texture during straight-rolling and cross-rolling of the CC 3003 aluminum alloy,and the evolution of the texture during rolling of the CC 5754 and DC 5052 aluminum alloys were studied by X-ray diffraction.The rotational path and stability of the rolling texture during cross-rolling and the factors affecting the evolution of the rolling texture of the alloys were analyzed.The results shows that the hot band of CC 3003 aluminum alloy has a strong β fiber rolling texture,and after rotating 90°around the normal direction,the typical B,S and C orientations on the β fibers are transformed into the B’{1 10}<1 1 1>,S’{1 2 3}<17 22 9>and C’{1 1 2}<1 1 0>orientations.These orientations are unstable and gradually rotated to the β fiber in the new sample reference system.During the cross-rolling process,the S’ orientation has the lowest stability during rolling,and the stability of the B’ orientation is higher than that of the C’ orientation.The evolution of the texture of CC 5754 and DC 5052 aluminum alloys during rolling was quantitatively analyzed using the JMAK equation,and it was found that the DC 5052 aluminum alloy has a higher formation rate of the β fiber rolling texture and disappearance rate of the remainder component compared with the CC 5754 aluminum alloy,and a lower disappearance rate of cube+r-cube component.The hot band of the aluminum alloy CC 3003 was cold-rolled to various reductions along the original rolling and transverse directions,and then it was annealed for various periods of time at 399℃ and 427℃.The findings demonstrate that the straight-rolled(i.e.,in the original rolling direction)sheets annealed at 399℃ have recrystallization textures that are characterized by the M and P components,with the M component significantly strengthening with increasing rolling reduction and the P component only slightly strengthening.The M texture diminishes noticeably when the annealing temperature increases from 399℃ to 427℃,but the P texture weakens very marginally.When the rolling reduction approaches 60%to 70%,the r-cube recrystallization texture is formed in the annealed cross-rolled(i.e.,along the original transverse direction)sheets,and the strength of the r-cube texture declines with increasing rolling reduction.The 90%crossrolled sheet that has been annealed at 399℃ forms the comparatively strong M and extremely weak P textures in comparison to the 90%straight-rolled sheet.With increasing rolling reduction,the size of recrystallized grains grows in sheets that are annealed at 399℃,but it shrinks in sheets that are annealed at 427℃.The recrystallization activation energy is 421 kJ/mol and 379 kJ/mol for straight-rolled and cross-rolled sheets with 90%deformation,respectively.Cross-rolling can effectively reduce the recrystallization activation energy and promote recrystallization.The hot band of CC 3003 aluminum alloy was cold-rolled to different reductions,and then annealed at 482℃ for 1 h under different pressures.High pressure heat treatment can refine recrystallized grains and weaken pinning effect.In the meanwhile,the aspect ratio increases from 0.18 to 0.72.Compared with atmosphere pressure,the fine precipitates disappear after pressurization,the number density of large precipitates increases and the average size of large precipitates decreases.The recrystallization textures are characterized by the weak P and R-cubeND components and a relatively strong M component under atmosphere pressure.The intensities of the P and M components increase with the increasing rolling reduction,while the R-cubeND component changes slightly.With the increase of pressure,the P and R-cubeND components strengthen,while the M component weakens significantly,nearly disappears.The hardness decreases slightly with the increasing rolling reduction in the sheets annealed under atmosphere pressure and increases slightly with the increasing rolling reduction after pressurization.In addition to that,the hardness increases slightly with the increasing pressure in the sheets with the same rolling reduction.Cold rolling the CC 5754 aluminum alloy to different reductions was followed by an hour of annealing at 537℃ under varied pressures.The changes in microstructure and texture were studied.According to the findings,high-pressure heat treatment restricts recrystallization,and the restriction effect is stronger as pressure rises.The refining impact of high-pressure heat treatment can refine recrystallized grains,and it becomes stronger as the rolling reduction gets higher.In addition,the size of the recrystallized grain of the DC 5052 aluminum alloy with the same high-pressure heat treatment condition is larger than that of the CC 5754 aluminum alloy.The variation of recrystallization texture is significantly affected by high-pressure heat treatment.The sheet with a 19.6%reduction is found to have a weak cube texture at atmospheric pressure and 2 GPa,but the sheet that has been annealed at 4 GPa and 6 GPa has a strong cube texture and a weak b fiber rolling texture,and the strength of the cube component of the DC 5052 aluminum alloy after annealing is lower than that of the CC 5754 aluminum alloy.High-pressure heat treatment improves the intensities of the cube and R textures in the fully recrystallized sheets with the same reduction.The strengthening impact of R texture from high-pressure heat treatment improves with increasing rolling reduction.