Numerical Simulation And Experimental Study Of Creep Sizing Process On2A14Aluminum Alloy

Due to the high requirements of precision aerospace components to size andshape, it is very important to reduce the internal residual stress in the workpiecewhen sizing it. Creep sizing process is a method that could meet this requirement. Increep sizing process, workpiece is sized under low stress, therefore the processwon’t bring much residual stress in workpiece.In creep sizing process, the deformation of workpiece is produced by moldloading. And the stress in workpiece will relaxed in the sizing period. As the stresslevel is low, there will be some stress keeping in the workpiece after part of thestress is relaxed as creep has happened. springback will happen when the workpieceis unloaded. So predicting the springback of sizing process is a critical part in thework of process designing, which is also a difficult problem of creep sizing process.Using the finite element method to design the sizing process is an effective means tosolve this problem.This paper has studied the effect of temperature an stress on creep behavior ofartificial aging2A14by run a series creep tests, and found that temperature makemore significant effect then stress. The value of stress index is2~4which means thecreep is stick-slip mechamisn of dislocation. By calculating the Arrhenius equationto obtain2A14-T6aluminum alloy180MPa creep under stress, the apparentactivation energy calculated value of creep is93kJ/mol, which is close to aluminumgrain boundary diffusion activation energy. By analysising and calculation of thecreep curve, constitutive equation of different temperatures of2A14-T6aluminumalloy creep is established. A tensile creep test finite element model based on theconstitutive equation is established. Compared the simulated creep curves withcreep test curve, the relative error is at most10.5%, which means the constitutiveequations can accurately describe the creep behavior2A14-T6aluminum alloy.On the basis of creep constitutive model, the paper establishes the finiteelement model to simulate creep sizing process. In order to verify the correctness ofthe model, the paper carry out a series creep forming experiment on3mm ofthickness sheet at different temperatures and holding time. By measuring the radiusof curvature and surface stress of sheets after springback, Achieved a simulate ofspringback rate error less than15%. By statistical analysis EBSD grain orientationof the sheets. Found that the deformation mechanism of forming in the initial stateis dislocation slip sticky, and slowed down in the latter part of the stress relaxationand deformation mechanisms translate into grain boundary diffusion creep, andthere is a dislocation dynamic recovery. Based on the creep sizing FE model, a sizing designing to size a sheet to2000mm curvature is carried out, and a sizing practice is run to vertify is. Designerror is10.25%, the engineering requirements is meeted...