| Because of its low density,high specific strength and good corrosion resistance,6xxx aluminum alloy is widely used in aerospace,automotive manufacturing and other fields.With the improvement of material performance requirements,people began to explore new materials processing with a view to get a good comprehensive performance.In this paper,6061 aluminum alloy was taken as the research object under different conditions of deformation and heat treatment,to study the impact of deformation,pre-aging and intermediate heat treatment on the 6061 aluminum alloy performance,which mainly includes hardness,tensile properties,electrical conductivity and corrosion resistance,the microstructural analysis of the samples treated by deformation and heat treatment was carried out from the aspects of microstructure,fracture scanning,XRD and transmission electron microscopy,the following conclusions were drawn:(1)The 6061 aluminum alloy hardness is highest when the aging temperature is 180? and the aging time is 4h after the solution treatment(540 ?,3h),the deformation before aging can not only improve the hardness and strength of the material peak aging,but also reduce the time to reach the peak aging,and the larger of the deformation,the higher of the hardness and strength,the shorter of the time to reach the peak aging,but the plasticity decreases.The final hardness of the sample without pre-aging treatment is 129.6HV,the tensile strength is 368.32 MPa,the elongation is 22.10%,when the deformation is 50%,the final hardness of the sample treated by pre-aging is 136.7HV,the tensile strength is 385.82 MPa,the elongation is 22.21%,its can be seen that the pre-aging effect can not only improve the hardness and strength of the material,but also improve the plasticity of the material.Under the same amount of deformation,the final hardness and strength of the sample with the highest peak in the middle are the highest,but the plasticity is the worst,the sample's plasticity with recrystallization in the middle is the best,but the strength is lower,the final hardness,strength and elongation of the sample subjected to the returned treatment are between the two.(2)The deformation after solution treatment will reduce the electrical conductivity of 6061 aluminum alloy,and the greater of the deformation,the more serious the reduction.The electrical conductivity of 6061 aluminum alloy will increase with prolong of the aging time,and the recovery and recrystallization treatment can improve the electrical conductivity of 6061 aluminum alloy,and the effect of recrystallization is bigger.(3)The deformation before aging can improve the corrosion resistance of 6061 aluminum alloy,and the greater of the deformation,the better of the corrosion resistance of the alloy.Under the same deformation conditions,the pre-aging before deformation will reduce the corrosion resistance of the 6061 aluminum alloy after aging.The corrosion resistance of the samples treated by recovery and recrystallization after deformation is better than that of the peak aging treatment,and the effect of the recrystallization treatment is more remarkable,different intermediate heat treatment methods have different effects on the final corrosion resistance of the material.(4)The deformation before aging will elongate the grain,and the greater of the deformation,the more obvious grain elongation,the recrystallization process after deformation will refine the grain.The deformation before aging not only affects the intensity of the diffraction peak,but also changes the position of the diffraction peak,the way of heat treatment after deformation will only affect the final diffraction peak intensity of the material,and not change the position of the diffraction peak.(5)The tensile fracture of 6061 aluminum alloy under different deformation heat treatment is tough fracture,deformation,pre-aging and intermediate heat treatment will affect the ultimate fracture morphology of 6061 aluminum alloy,the biger amount of deformation before aging,the fewer the number of large dykes at the fracture,the more shallow the dimple,the worse plastic,the pre-aging before the deformation can improve the plasticity of 6061 aluminum alloy after aging.After the deformation of the sample after recrystallization grain refinement,and then after deformation of aging,the fracture evenly distributed dimple,the number of large dimple and dimple deeper,better plastic.(6)The deformation before aging will produce a large number of dislocations.The larger of the deformation,the more serious of the dislocation tangles and the uneven distribution,when the deformation amount is 50%,the deformed sub-structure is produced.The deformed sub-structure produced by the pre-aging treatment is more obvious and the size is more uniform and the plasticity is better.Reply treatment after deformation,the dislocation density in the crystal is slightly reduced and the vacancy disappears.Recrystallization treatment after deformation,the dislocation disappears,and then the deformation is dislocated and the strength of the alloy is increased. |
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