Simulation And Experimental Study On Upsetting-torsion Severe Plastic Deformation Of 5A06 Aluminum Alloy

Severe plastic deformation process used large strain to refine the material structure and improved the mechanical properties.It was difficult to achieve the unity of large size sample and high efficiency grain refinement in SPD process.In this paper,a new process of upsetting-torsion severe plastic deformation was proposed.The material was deformed by means of upsetting and high pressure torsion alternately,which used to prepare large size ultrafine grain material.The upsetting-torsion severe plastic deformation process of5A06 aluminum alloy was simulated by finite element method,and the process parameters were optimized.Finally,the ultrafine grain aluminum alloy with excellent mechanical properties was prepared by process experiment.The stress strain curves under different deformation conditions were obtained by hot compression experiment.The constitutive model was fitted by hyperbolic sine function.The recrystallization volume fraction model and grain size model were established according to the microstructure after hot compression.The model was embedded into Deform-3D software by Fortran program language to simulate the stress strain and microstructure distribution during upsetting-torsion severe plastic deformation process.Two passes of upsetting-torsion severe plastic deformation process were carried out on the blank,and the process was optimized by finite element simulation.In addition,the distribution of upsetting parameters,height diameter ratio and deformation angle were analyzed.Isight software was used to optimize the deformation parameters and the best deformation process parameters were obtained: the first upsetting reduction was 5.900 mm,the second upsetting reduction was 3.100 mm,the height diameter ratio of the sample was0.750,the torsion angle was 225 °.The error of Isight optimization results and finite element simulation results was within 3%.The equivalent strain and the distribution and change law of microstructure after deformation under different temperatures were analyzed.According to the results of Isight optimization,upsetting-torsion severe plastic deformation experiment was carried out to prepared 5A06 aluminum alloy ultrafine grain material,and the experimental temperature was 200??350?.The microstructure of the material prepared at different deformation temperatures was analyzed,and the mechanical properties at room temperature were tested.The results showd that the grain size of the material could be refined to 200 nm,the fracture strength was more than 400 MPa,and the elongation was 28.29%.