| Under the background of energy conservation and emission reduction and lightweight of automobile,aluminum alloy materials are gradually replacing steel and widely used in forging parts in suspension system of passenger vehicles.The 6082 Al-SiMg aluminum alloy is forged to control arms,most of which are intricately shaped.Their flowlines,mechanical properties and internal structure are requested strictly.In this paper,the high temperature deformation behavior of 6082 aluminum alloy was studied.Constitutive equation and the microstructure evolution equation were obtained,then introduced to DEFORM.The flow law and internal structure evolution of the material in the multi-directional press process were simulated.And the multi extrusion process is verified by the experiment of two typical L and Y branch aluminum alloy control armesThe thermal deformation behavior of 6082 aluminum alloy at high temperature was studied by thermal simulation ewperiment.The high temperature rheology equation was obtained at different temperature and strain rate.Considering the effect of strain on the flow stress,the 3 order polynomial was used to compensate the strain.The rheological stress was obtained at any temperature,strain rate and strain.The hot processing maps of 6082 aluminum alloy was set up according to the Prasad instability criterion.The optimum forming temperature of the material was 530 ℃-540 ℃ and the strain rate range 0.01s-1-0.3s-1.EBSD method was used to analyze the grain morphology and recrystallization fraction of compressed samples at different deformation temperatures and strain rates.The columnar grain is in the majority before deformation.Columnar grain still occupies the main position and minute quantity of equiaxed grain appears between the columnar grains after the deformation in hard deformation zone,which shows that the softening mechanism of the material is mainly dynamic recovery.Columnar grains in the large deformation zone and the small deformation zone disappear,the equiaxed grains form,indicating the softening mechanism is dynamic recrystallization.The ratio of High Angle Boundary to Low Angle Boundary is large in large deformation zone and small deformation zone,and Low Angle Boundary occupies a great proportion in the hard deformation zone.The average grain size and the recrystallization fraction under various deformation parameters were obtained.The relationship between the average grain size and the Z parameters and the variation trend of the recrystallization fraction with the Z parameters were obtained.The critical strain of 6082 aluminum alloy under different deformation conditions was obtained by the relationship between the harden ing rate and the strain.Then the evolution equation of the recrystallized grain size and the dynamic recrystallization fraction was obtained.The constitutive equation and the microstructure evolution equation of high temperature are verified by DEFORM si mulation.The results show that the model can effectively predict the forming force and the internal microstructure evolution process.In the multi direction press process of Y and L type aluminum alloy control arms,mental flow law,forming press and clamping force are studied.Multi direction hydraulic press is used to verify the two kinds of forming processes.The problems in the muti press process are analyzed and the solutions are put forward.The results show that the multi-directional press process can produce two different types of aluminum alloy control arms.The performance of the forgings is the best under the solid solution temperature is 540℃-2h and the aging temperature 170℃-5h~8h... |
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