Experimental Research And Numerical Simulation Of Hot Deformation And Dynamic Recrystallization Behavior Of7050Aluminum Alloy

7050aluminum alloy, as a kind of high-strength aluminum alloy of Al-Zn-Mg-CuSeries, has rapidly developed into important structural materials in the aerospace fieldsince invented in1937based on7075aluminum alloy because of its excellentcomprehensive performance, such as high strength, high toughness, resistance tocorrosion and low density, and its forgings are widely used as aircraft landing gearbulkhead, wing beam and bearing bracket, etc. Therefore, it is of great engineeringsignificance to research the high-temperature deformation behavior and microstructureevolution of7050aluminum alloy for formulating appropriate forming process offorgings. The characteristics of deformation under loading during thermal compressionprocess and hot forging process have many similarities, which result in their dynamicrecrystallization behaviors also have same similarities to some extent, consequently,studies on dynamic recrystallization evolution by thermal simulation experiment have areference value on researching dynamic recrystallization evolution during forgingforming process. Simulating forging forming using finite element method can not onlyshorten the mold development cycle, save the mold cost to create economic value, at thesame time, also has an important guiding significance on improving the formingtechnology and controlling forming quality.In this paper,7050-H112aluminum alloy ischosed as research object, the flow behavior and dynamic recrystallization evolution of7050aluminum alloy at high temperature are studied throught the hot compressionexperiment with the help of mathematical regression analysis, metallographicmicroscopy, EBSD analysis technology and finite element simulation technology.Themain contents are as follows:①The flow stress curves are obtained and the flow constitutive equation is builtby compressing7050-H112aluminium alloy under the deformation of60%,the strainrate of0.01s^-1,0.1s^-1,1s^-1,10s^-1and the temperature of300°C,350°C,400°C,450°C usingGleeble^-1500D thermal simulation testing machine. Studies show that7050aluminumalloy has a positive strain rate sensitivity index, it prone to dynamic recrystallizationwhen strain rate is small, otherwise, prone to dynamic recovery.②The critical conditions of dynamic recrystallization occurs are studied and thedynamic recrystallization critical strain model,the dynamic recrystallization volumefraction model, and the dynamic recrystallization grain growth model are established based on the data from hot compression test experiment. The results show that dynamicrecrystallization takes place when7050aluminum alloy was deformed under the alldeformation conditions mentioned above.③With the help of the flow stress constitutive equation and dynamicrecrystallization model have been established, hot compression process was simulatedbased on DEFORM-3D by applying finite element methold. The results prove that thedistributions of dynamic recrystallization volume fraction and grain size are unevenunder the influence of uneven deformation. Dynamic recrystallization is complete andgrain size is smaller in central large deformation zone,while in marginal harddeformation zone dynamic recrystallization is more difficult to occur and the grain sizeis bigger,in free deformation zone dynamical recrystallization is halfway, the grains aremischcrystal and their size range between the center and marginal.In addition, theevolution rule of dynamic recrystallization during the forming process of7050aluminum alloy forgings are also researched.