The Visco-elasto-plastic Constitutive Model Of ZL205A Alloy During The Solidification Process And The Deformation Rules Of Cylindrical Shell

The stress/strain constitutive model in the process of solidification possesses highly theoretical and practical significance for the improvement of the stress field simulation accuracy and practical level.Among all the model,the constitutive model in high temperature stage is especially important.Nevertheless,at present,the research of the constitutive relations of the stress/strain constitutive model in high temperature stage is insufficient,the lack of high temperature mechanical property parameters test of casting material in our country,and the related database is still in the blank stage,all above bring numerous difficulties to the study of stress/strain constitutive model in the solidification process.Stress-strain curves at different temperatures were obtained by the tensile test of ZL205 A alloy.And parameters of mechanical property were subsequently calculated according to the test data.Thus,the VEP model simulation can be performed by using these parameters combined with some thermodynamic parameters obtained from literatures.The stress frame specimen was applied to simulation considered linear elastic model,EP model and VEP model respectively.The results showed that the data of temperature field simulation is consistent with experimental result,while discrepancies were found between stress field simulation and experiment.Nevertheless,the result of the VEP model simulation is closest to the experimental one.Same methods were applied to a hot cracking specimen,where simulation data were compared with experimental data obtained from casting test.As a result,the VEP model was superior to the linear elastic model and VP model.Finally,we simulated the solidification process of the large-sized thin-wall cylindrical component by using VEP model.The results indicate that stress is concentrated at the intersection of the flange and the thin-wall.In addition,the stress at the outside of the thin-wall is higher than the inside one,which leaded to a warping deformation in the cylindrical component.By comparing the stress value and deformation of different height of tiepiece in cylindrical component,a conclusion can be drawn that the higher the tiepiece,the lower the stress and deformation.When the height of tiepiece increased from 19 mm to 48 mm,cylindrical pieces in the flange and the stress of the thin-walled junction fell by half,deformation reduced by a quarter.