| Inconel 718 superalloy is the most widely used nickel-based superalloy in the field of aircraft engine.The strengthening mechanism is dominantly precipitation strengthening.As a result,complex precipitates and their properties will have great influence on the properties of the alloy.Multi-scale simulation including first principle studies and crystal plasticity finite element method is used to estimate the properties of different phases in Inconel 718 superalloy.First principle is used to calculate material properties such as lattice parameter,thermodynamic properties,elastic properties and hardness.This study presents an atomic scale understanding of precipitate properties,and provides theoretical evidence that may improve the overall performance of alloy.Crystal plasticity finite element method(CPFEM)based on dislocation density and concerned parameters were investigated using ABAQUS.The crystal plasticity constitutive laws can reflect the mechanical properties accurately.The crystal plasticity parameters of Inconel 718 were calibrated with the comparison between RVE simulation and tensile test.It is proved that the calibrated parameters can embody the mechanical properties of Inconel 718.Therefore,it is made possible to study the meso-scale mechanical properties at grain size.Nanoindentation test combined with crystal plasticity finite element simulation is used to estimate the mechanical properties of precipitate in Inconel 718 superalloy.The simulation results appeals that the pile-up pattern and out-of-plane deformation is closely related to crystalline orientation.Elastic properties calculated by first principle are quite accurate,while the yield stress estimated from hardness has significant error.Therefore,inversion calculations are carried out to determine the yield stress.This multi-scale simulation is a feasible approach to estimating the mechanical behavior of large precipitates on the nickel-based superalloy. |
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