| Lightweight is an effective way to solve the energy crisis,environmental pollution and safety problems.Aluminum alloy as the main vehicle lightweight material,the domestic and foreign government,enterprise and researchers pay more and more attentions to it,and Al-Mg-Si alloy with its excellent comprehensive performance has become the preferred material for automotive lightweight.However,the aluminum alloy sheet in the process of natural aging process of the "parking effect" and the baking hardening speed and other issues,restricting its extensive application in the actual production.In this paper,6016 aluminum alloy was used as the research object.Effects of heat treatment and pre-deformation on the microstructure and properties of AlMg-Si aluminum alloy for automobile body and the evolution of texture during cold rolling were studied by OM,scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),transmission electron microscopy(TEM),hardness test,tensile performance test,forming performance test and other means of observation and testing.Microstructure and macroscopic mechanical properties are combined and the heat treatment and processing technology are adjusted this paper,it try to find the technological parameters that can speed up the alloy enhanced phase precipitation and reduce the bad influence during the natural aging.The main conclusions are as follows:(1)The mechanical properties of T4 sheet produced by conventional solid solution water quenching are influenced by natural aging,and the hardening value of paint is not high.The twostage quenching process can effectively inhibit the effect of natural aging on the mechanical properties of the sheet to a certain extent,but also promote the rapid aging of the alloy sheet.However,if the quenching temperature is too low(70 ?),the natural aging of the plate is not obviously inhibited,and quenching temperature is too high(130 ?),the strength of alloy sheet is too high before paint baking,it is bad for stamping.Therefore,when the quenching temperature is centered(100 ?)and the holding time is 50 min ~ 60 min,the inhibition effect of natural aging is obvious,and the hardening effect is the highest.(2)As the extension of the quenching time,the earlier the hardness of the plate reaches the peak,but the peak hardness first increases and then decreases.When the holding time is 40 min ~ 60 min,the peak hardness of the alloy is 108 HV ~ 110 HV,and the peak hardness occurs between 60 min ~ 90 min.When the natural aging time is less than 1 day,quenching and heating 5min ~ 20 min can greatly promote the aging time of the paint plate.When the natural aging time is 1 ~ 3 days,the quenching and holding time needs 40 min ~ 60 min in order to effectively promote the hardening efficiency of paint.In the natural aging time in more than 1 week,the quenching time to be maintained between 50 min ~ 60 min,in order to make the paint alloy sheet to meet the actual production needs.(3)With the increasing of cold rolling deformation,the dislocation density in the alloy increases gradually and the strength of the plate gradually increase,the plasticity decreases gradually,and the inhibition effect of the alloy sheet on the natural aging is also more obvious.After paint aging,the yield strength and tensile strength of the plate are increased,and the elongation rate also has a small increase.In the paint aging,the yield strength and tensile strength of the plate have increased,and the elongation also has a small increase.,With the increasing of deformation,time is shortened reaching peak hardness at the same aging temperature,and the peak hardness is higher.(4)With the increasing of the deformation,the typical deformation texture Copper {112} <111>,S {124} <211> will gradually replace the recrystallized texture Cube {001} <100> and become the main and stable orientation.When the deformation is less than 20%,the grain orientation is mainly {001},{012} orientation,and When the deformation is greater than 40%,the grain orientation becomes {011},{112},{123} orientation.When the deformation amount of the alloy is large,the deformation zone is formed between the grains,and the texture type of the deformation zone is mainly Copper {112} <111> texture and weak Cube {001} <100> texture composition. |
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