Effect of pulsed current on the deformation behavior of AZ31B magnesium alloy

The tensile tests of AZ31B magnesium alloy were carried out at the temperatures of 473–573 K and the nominal strain rates of 0.001–0.1 s−1 with or without pulsed current. The experimental results show that the electroplasticity effect does exist, which refutes the viewpoint that all the decreasing of stress in electrically-assisted forming is caused by Joule heat. It is also found that the effect of electroplasticity under a specific temperature exists a saturation value, and the pulsed current delays the occurrence of dynamic recrystallization of the specimens by accelerating the dislocation annihilation. Moreover, a parameter called the reduction of flow stress was defined to describe the intensity of electroplasticity effect. A mathematical model was proposed to describe the coupled relationship of the reduction of flow stress with deformation temperature, strain rate and strain, which can be also used to transform the constitutive relation without current to the constitutive relation with pulsed current.