Experimental And Modeling Investigations Of The Heat-treatment Residual Stress Evolution In GH4169 Superalloy

Compared with other alloys,GH4169 nickel-based superalloy is widely used in aerospace and other industrial fields in China due to their excellent high temperature performance and low relative cost.It is one of the indispensable materials for the development of national defense technology,especially in aviation.It is widely used in the manufacture of components such as turbine disks of engines.Despite the decades of history in China's research and development,compared with the research and use of the same kind of materials abroad,the GH4169 alloy produced in China is still not leading the world in terms of fatigue resistance,high temperature resistance and service life,and the residual stress introduced by the manufacturing process is one of the most important factors affecting its performance and service life.Therefore,systematically studying the formation and evolution mechanism of internal residual stress of GH4169 alloy is of great significance for optimizing the control of residual stress and improving the service life of materials.In this paper,the residual stress generated by quenching heat treatment and aging heat treatment after quenching for the initial solid solution GH4169 superalloy cylinder specimens was measured by the contour method,and then compared with the finite element simulation prediction results,and the correctness of the proposed constitutive relationships were validated.Based on the principle of the contour method,the two sets of samples were split into half by a wire electric discharge machine,and the profiles of the cut section due to the residual stress release were scanned by a fully automatic coordinate measuring machine.The contour data were averaged and surface-fitted,and the contour data were converted into stress data by finite element calculation.Finally,the residual normal stresses distribution of the GH4169 specimen on the cutting section after quenching and after quenching and ageing were obtained.During numerical simulations,the elastic modulus and the yield strength at different strain rates,and the relationship between work hardening and temperature change of GH4169 alloy,were calibrated by the high temperature uniaxial tensile test.And the sequential thermal-mechanical coupled constitutive model was applied to simulate the temperature change and thermal stress evolution of the specimen during quenching,and the residual stress prediction results are compared with experimental results using the contour method,verifying the correctness of calculated model.For the aging heat treatment after quenching,this paper developed a user material subroutine for finite element simulation based on a constitutive model that considers strengthening phase precipitation,and studied the evolution of residual stress in the sample during aging heat treatment.The applied constitutive model was validated by the comparison between experimental and analyzed results.