Effect of Angle between Pulse Current and Load Direction on Flow Stress of Ti-6Al-4V Alloy under Uniaxial Tension

In the research field of pure electroplastic effect, uniaxial tensile tests of Ti-6Al-4V alloy were carried out. By changing the position of the electrode, the pulse current with different angles was applied to the stretched specimen, to verify whether the angle between the current direction and the load direction affected the flow stress of the metal. The results show that as the angle between the current and the load direction increases, the stress drop of the material decreases, when the angle increases to 90°, the stress drop of the material was almost 0 MPa. Based on the experimental data, a variable describing the current direction was introduced to the JC model, and a constitutive equation considering the current direction for Ti-6Al-4V under the condition of pulsed current and room temperature was constructed. The verification results showed that the prediction accuracy of this constitutive equation was satisfactory. The influence mechanism of current density and direction on material flow stress was further analyzed by means of HRTEM, the smaller the angle between the current and the load direction, the higher the mobility of atoms at the grain boundaries of the material, and the phenomenon of dislocation packing is alleviated.