Tailoring the Microstructure Evolution and Flow Stress of Aermet100 Steel: High Temperature Electroplasticity based on Dislocation Vibration

An electroplasticity method for tailoring the flow stress during the thermal deformation of Aermet100 ultra-high strength steel by adjusting the frequency of electropulsing is proposed. This study rigorously controls the electron wind force and Joule heating effect to establish the origin of the electroplastic effect from the perspective of dislocation vibration for the first time. By strictly controlling the electron wind force and Joule heating effect, the origin of the electroplastic effect is verified for the first time from the perspective of dislocation vibration. The results show that the electropulsing frequency of 50 Hz has the lowest flow stress. Moreover, the flow stress of the specimens was nonlinear dependent on the increment in the electropulsing frequency, that it rose first followed by a decline. The electropulsing frequency threshold that can result in the transition in flow stress is 500 Hz. It is attributed to the proximity of the dislocation vibration frequency of Aermet100 steel at high-temperature conditions to the pulsed current frequency, leading to an increase in dislocation amplitude. Furthermore, a pulsed current frequency of 1000 Hz is found to have the highest recrystallization nucleation rate and recrystallized content. It is the threshold for the transformation of grain refinement strengthening. This investigation sheds new insight into the regulation of flow stress and microstructure in Aermet100 ultra-high strength steel using electroplasticity effect.