Researches On Tensile Properties And Fatigue Behavior Of Ni-based Alloy GH4169 Based On Crystal Plasticity Finite Element

Ni-based superalloy GH4169 is an important kind of material which largely used for the manufacturing turbine disks in aviation.The reliability and service time of the aero-engine are mainly depended on its properties.Therefore,the accurate life assessment is very important for this alloy.In previous studies,the traditional fatigue life prediction methods are mainly based on fatigue experiment,which are costly and time-consuming.Aiming at the above problems,the crystal plasticity finite element method was used to evaluate the fatigue life of GH4169 alloy.The main contents and conclusions are summarized as follows:(1)The microstructure of GH4169 alloy was established by using voronoi diagram method,and the crystal plasticity constitutive model was adopted to describe the mechanical properties of GH4169 alloy.The parameters of crystal plasticity constitutive model were identified by uniaxial tension and fatigue experiment.(2)The fatigue crack initiation life of GH4169 alloy under different strain amplitude was studied.The results showed that the accumulated plastic slip of microstructure model was increasing with the increase of the strain amplitude of GH4169 alloy,and the predicted fatigue crack initiation life was lower,and the orientation of the single grain has greater effected on the accumulated plastic slip;(3)The effects of different initial defects on the fatigue life of GH4169 alloy were investigated.With the increase of defect size,the fatigue crack initiation life of GH4169 alloy decreased gradually.When grain orientation had a competitive effect with stress concentration of the structure on the crack initiation,grain orientation had greater effected on crack initiation.