Effect of Electric Pulse-Assisted Extrusion on the Dynamic Recrystallization and Mechanical Properties of AZ31 Alloy

AZ31 Mg alloy with homogeneous refined microstructure and exceptional mechanical properties is obtained by electric pulse-assisted extrusion in this article. The effect of the electric pulse on the recrystallization behavior of AZ31 alloy extruded at 423K is studied. The results show the recrystallization degree increases with increasing the current density, frequency, and pulse duration, respectively. Compared to the conventional extrusion samples at the same temperature, 423K, the DRX degree of the EPAE-3 sample is increased from 11.3% to 80%, the corresponding yield strength, ultimate tensile strength, and tensile elongation to falur are improved from 322 MPa, 375 MPa, and 11.5% to 338 MPa, 404 MPa, and 16.8%, respectively. The dynamic recrystallization (DRX) and grain refinement mechanism of the electric pulse-assisted extrusion is discussed, and the athermal effect of the electric pulse is considered to play a dominant role by increasing the nucleation rate and the vacancy diffusion flux.