Compression deformation mechanism and constitutive description of nickel-based superalloy based on electroplasticity effect

Based on the electroplasticity effect, the split Hopkinson pressure bar (SHPB) experiments were conducted on nickel-based superalloy GH4169 under electrically assisted conditions. The dislocation morphology induced by pulse current during material deformation was studied, and the dynamic mechanism of dislocations under the electroplasticity effect was analyzed. According to the experimental results, it was found that the addition of pulse current reduces the dislocations pile-up in the material, promotes dynamic recrystallization, and thus improves the plasticity of the material. To further investigate the effect of electric field on nickel-based superalloy GH4169, the first principles calculation method was used to analyze the influence law of electric field on the phase structure of Ni- γ Phase, AlNi₃- γʹ, NbNi₃- γ″. The simulation results show that the application of an electric field reduces the shear modulus and Young's modulus of the material, making it prone to deformation, which is consistent with the results of the pulse current assisted compression experiment. Finally, based on the dislocation thermal activation theory and the Johnson-Cook constitutive model, the energy obtained by dislocations from free electrons and magnetic fields was analyzed. The constitutive equation under pulsed current is established, and the high accuracy of the established constitutive model is verified through experiments.