Effect of pulsed current on plastic deformation of Inconel 718 under high strain rate and high temperature conditions

Abstract

Based on the electroplastic effect induced by pulsed current, the dislocation states induced by pulsed current during material deformation were studied by introducing pulsed current into the Split Hopkinson Pressure Bar (SHPB) experiments with Inconel 718 as the research object, and the dislocation kinetic mechanism under the electroplastic effect was analyzed. Simulations and experiments’ results show that pulse current can promote the unpinning movement of dislocations and effectively improve the state of dislocation pileup. At the same time, it is found that the current can produce a similar skin effect on the excited magnetic field, so that the magnetic field is mainly concentrated on the surface of the material. The magnetic field are concentrated on the symmetry axis, and gradually decreases from the surface to the central axis. Finally, the dislocation slip theory is combined with the local energy-state theory which describes that the electronic wind force can reduce the dislocation energy barrier and the magnetic field change the dislocation magnetic core, and the relationship between the plastic deformation rate and the current density under the combined action of the electronic wind force and the magnetoplastic effect is deduced. At the same time, the obtained relationship is brought into the constitutive equation to obtain the constitutive equation under the pulse current. Through experimental verification and error analysis, it shows that in the range of current density 0∼0.2A/mm−2, the calculated stress-strain curve is consistent with the stress-strain curve obtained in the experiment.