Study On Microstructure Evolution And Numerical Simulation Of 7075 Aluminum Alloy At High Temperature

In this paper,7075 aluminum alloy was taken as the research object,and the high temperature torsional behavior of 7075 extruded aluminum alloy was studied by using the first Gleeble-3500 thermal simulation tester in domestic universities.The effects of different deformation parameters on the evolution of fiber tissue were analyzed.Based on the combination of physical experiments and finite element numerical simulation,the research on the microstructure evolution and texture prediction of the hot forming behavior of the alloy was carried out.The reliability of the above simulation prediction results was verified by comparison with experimental results.The main conclusions are as follows:(1)During the high temperature torsion process,the degree of deformation of the sample is continuously increased,and the shape change of the crystal grains is significantly different.According to the change of the axial to surface grain shape of the sample,it can be divided into three regions: fibrous grain region,elliptical grain region,and equiaxed grain region.(2)Analysis of microstructure changes of 7075 aluminum alloy after hot torsion:At the same strain rate,the grain size becomes smaller as the degree of deformation increases,and the fractional fraction of the small-angle grain boundaries also decreases.There is still a residual <111> silk texture in the parallel ED direction in the bar.When the deformation temperature increases,the grain size of the same deformation zone and the proportion of the small-angle grain boundary become smaller.The orientation density of the grains is reduced and the maximum intensity position of the texture is changed.At the same deformation temperature,the degree of deformation increases,the sample undergoes uneven deformation,and the maximum strength position of the texture changes.As the strain rate increases,thegrain size tends to gradually increase,and the fractional fraction of the small-angle grain boundary increases.The orientation of the grains is constantly changing,and the maximum intensity series of the texture exhibits an irregular change.(3)Dynamic prediction of the deformation process of 7075 aluminum alloy specimens using DEFORM-3D computer numerical simulation technology:At the same strain rate,the equivalent stress decreases with increasing deformation temperature.The entire part of the sample has undergone different degrees of deformation,and the distribution of equivalent strain is not uniform.The polar density position of the pole figure obtained by numerical simulation is basically consistent with the physical experiment,but there are some errors in position and physical experiments.At the same deformation temperature,the equivalent stress increases with the increase of the strain rate.