Study On The Unified Constitutive Model Of Internal Variables Based On The Evolution Of Dislocation Density And Dynamic Recrystallization

7075 aluminum alloy has good mechanical properties and anodic reaction.After heat treatment,high strength characteristics can be obtained.Most importantly,it is stronger than any mild steel.Especially suitable for aircraft structure and other industrial needs of high strength,chemical corrosion resistant structural parts.In this paper,instron-5899 electronic universal testing machine is used to explore the mechanical behavior of 7075 aluminum alloy in the process of hot compression forming,which provides a theoretical basis for improving the mechanical properties of 7075 aluminum alloy after hot deformation.The research scheme and results are as follows:(1)Through homogenization treatment and isothermal warm compression try,and the impact of distinctive warm distortion conditions on stream stretch is considered.Taking dislocation density,grain size and dynamic recrystallization volume fraction as internal variables,a 7075 aluminum alloy model based on the change of material microstructure was established.The optimized immune algorithm was used to calculate the material constants in the model to determine the constitutive model.The optimal solutions of 13 material constants and statistical verification of the model have verified the accuracy of the constitutive equation.(2)The effects of different deformation parameters on the microstructure evolution of 7075 aluminum alloy during hot compression were investigated.The comes about appear that the normal grain measure diminishes with expanding strain rate and diminishing misshapening temperature.The fitted energetic recrystallization condition is pertinent to portray the recrystallization behavior and grain advancement behavior of 7075 aluminum combination.Based on the isothermal hot compression tests,the energetic recrystallization advancement of the microstructure amid the warm misshapening of 7075 aluminum amalgam was recreated.Based on the DMM theory and Prasad's destabilization criterion,the optimum thermal processing interval of 7075 aluminum alloy was determined by analyzing the power dissipation rate and destabilization criterion under different deformation conditions and establishing the thermal processing diagram in time.