Microstructural Evolution Near Microcrack in AZ31 Mg Alloy Under Electropulses

Electropulsing treatment (EPT) is a novel method utilizing the Joule effect for efficient metal heating. EPT's advantages over traditional furnace methods have led to growing interest, particularly its defect-repair potential at sub-melting temperatures. Our study introduces an alternative EPT process using direct current (DC) for reduced energy consumption and enhanced scalability. The research involves applying square wave pulses with varying current densities to AZ31 magnesiumMagnesium, examining microstructural changes in pre-cracked sheets under EPT. Subsequent fatigueFatigue tests induce controlled pre-cracks, revealing localized welding around the cracks post-EPT. The study diverges by proposing a “current detour effect” and a point-wise current source amplifying the Joule effect for defect repairDefect repair. Observed {10−12} extension twins support the hypothesis, attributed to the compressive stress from EPT. However, calculated thermal compressive stress remains below the CRSS for the {10−12} twin. Distinct recrystallizationRecrystallization kinetics, such as continuous static recrystallization, might be influential around the entire crack regions.