Study On High Temperature Deformaiton Behaviour Of 7075 Aluminum Alloy And Numerical Simulation

7075 aluminum alloy belongs to ultra high strength aluminum alloy,and has good comprehensive mechanical properties.It is a lightweight and high strength structural material,and is mainly used in aviation fields.However,the alloy has poor plasticity at normal temperature and is usually plastically processed at high temperature.Therefore,the study of high temperature deformation behavior of 7075 aluminum alloy can provide a basis for its plastic forming process.In this paper,a uniaxial isothermal compression test of rolled 7075 aluminum alloy samples was carried out by using Gleeble-3500 thermal simulation test machine,and the treated specimens were treated with solution and aging.The flow stress behavior of 7075 aluminum alloy deforming at high temperature was studied and the constitutive equations of flow stress was obtained.At the same time,the microstructure evolution of the alloy during high temperature compression deformation was analyzed,and the recrystallization law of the alloy was discussed.Finally,DEFORM software was used to simulate the compression deformation process of 7075 aluminum alloy sample,and the detailed law of deformation can be obtained.The main conclusions are as follows:(1)The dynamic softening was mainly due to dynamic recovery when 7075 aluminum alloy was deforming at high temperature.And the deformed microstructure shows typical characteristics of continuous dynamic recrystallization.(2)Obvious dynamic recrystallization occurred,the primary grain boundaries disappeared and many small new grains were formed when 7075 aluminum alloy was compressed at 480? under a strain rate of 0.01s-1.Static recrystallization did not occur in 7075 aluminum alloy during solution and ageing after deformation at high temperature.(3)The flow stress depends on the deformation temperature and strain rate.The flow stress decreases with the increase of temperature and increases with the increase of strain rate.7075 aluminum deforming at high temperature,the constitutive equation of flow stress is:?=3.565 × 1012[sinh(0.0174?]4.667 exp(-1.847×105/RT)(4)The effective stress field of these specimens can be divided,and the effective stress is close to the corresponding true stress value.The load obtained by simulation is close to the actual load.