Prediction Of Quenching Deformation Of Aerospace Aluminum Alloy Large Components Based On UMAT

Nowadays,integrated manufacturing is increasingly being used in the aerospace industry.Its excellent mechanical properties,durability make th e manufacturing method one of the main manufacturing methods in aerospace industry.However,the quenching deformation has always been an important bottleneck restricting the development of the manufacturing technology.According to statistics,in all scrapped components,the quenching deformation is 70%.Such components are often large in size,complex in structure,uneven in wall thickness and thin in whole.These characteristics make the stiffness of components lower,so they are prone to large deformation during quenching process.At present,technological trial and error and artificial proofreading are the main quenching deformation control methods,but due to the lack of temperature-stress-deformation coupling mechanism research,and the existing constitutive model can not be applied to engineering.In application,the quenching deformation process cannot be accurately predicted and controlled.The object of this paper is high-strength cast aluminum alloy ZL205 A,which is widely used in large-scale aerospace structural parts.The tensile true stress-strain curves of the alloy at different strain rates were obtained by quenching tensile test.Through analysis,it is found that ZL205 A alloy has obvious mechanical properties difference between 298-473 K and 573-773 K.Based on the thermal activation mechanism,the mechanical constitutive model of Arrhenius-type is established in two temperature ranges,which lays the foundation for subsequent simulation analysis.Using the user subroutine of the simulation analysis software ABAQUS,the obtained wide temperature quenching constitutive model of ZL205 A aluminum-copper alloy was applied to the user program UMAT embedded main program by using Fortran.The subroutine uses J2 flow theory combined with radial return algorithm and Newton iteration method to consider the influence of temperature,strain and strain rate on the material’s current yield stress,and calculate the plastic strain and flow direction of the material.The quenching tensile test was simulated using this subroutine to verify its correctness.A finite element model of solid solution quenching for a large-scale thin-walled structural part for aerospace is established,and the wide temperature constitutive UMAT is used for simulation.In the simulation,the inclination phenomenon of the component in the process of entering quenching fluid is considered,and compared with the situation of horizontal entry into the quenching liquid,The reason for the upwarping on one side of the component is explained.The technological idea of sacrificing quenching transfer time to ensure the horizontal entry of components into quenching liquid is proposed.The result prove that the upwraping deformation on one side is reduced from 15 mm to less than 5mm which satisfies the design requirements.