Study On Hot Deformation Behavior Of 7A85 Aluminum Alloy And Simulation Of Aviation Forging Process

7A85 aluminum alloy is a new generation of high strength alloys in line with the development trend of contemporary aircraft,and has attracted much attention in aviation manufacturing because of its excellent mechanical properties.In order to promote the industrial application of the alloy,it is urgent to study the heat treatment of 7A85 aluminum alloy.In this paper,a 7A85 aluminum alloy aviation die forging was used as the object of study.The hot-compression test was carried out on the Gleeble-3800 thermal simulator with hot-compressed samples of 7A85 aluminum alloy heated to 400 ° C for 5 minutes.The true stress-strain curve of the alloy was tested under the conditions of deformation temperature of 320?-440? and strain rate of 0.01s-1-10s-1.The influence of deformation temperature and strain rate on flow stress was analyzed.The constitutive equation considering the effect of strain and the processing maps for hot deformation was developed.The microstructures of 7A85 aluminum alloy hot compressed water quenched samples were tested by metallographic and EBSD experimental methods.The relationship between the thermal deformation structure and the deformation temperature and the strain rate of the alloy was analyzed.The grain boundary orientation and the nucleation mechanism of the equiaxed crystal were discussed.And the evolution of 7A85 aluminum alloy thermal deformation structure was revealed.Based on the above results,a feasible process window and its process parameter range were selected from the two safety processing areas of the thermal map.With the application of DEFORM-3D finite element simulation software,the numerical simulation of forging forming process of 7A85 aluminum alloy forging with mass of about 50 Kg and maximum projecting area of about 0.4m2 was carried out under the deformation conditions of forging temperature 350~440?,hydraulic machine moving beam pressing speed5~20mm/s,between the forgings and mold friction coefficient 0.1~0.5,mold preheating temperature 200~350?.The effects of deformation temperature and hydraulic shear rateon the forging temperature field,the equivalent strain field and the maximum forming load were analyzed.And got a reasonable value of 7A85 aluminum alloy forging forming forging temperature,hydraulic press moving beam pressing speed and mold preheating temperature.