Improvement of Formability and Corrosion Resistance of Az31 Magnesium Alloy by Pulsed Current-assisted Laser Shock Forming

Abstract

This study adopted a novel pulse current-assisted laser shock AZ31B sheet micro-forming method (EP-LSF). The mechanism of improving the formability of AZ31B Magnesium Alloy by pulse current assisted laser shock forming and the reason of improving the corrosion resistance were studied for the first time. Through laser shock free bulging experiment, tensile test, optical microscope (OM), and X-ray diffraction, the change in formability was studied. After pulse current assisted laser shock forming, the forming height of AZ31B magnesium alloy increases by 28.8%, the thinning rate decreases by 6.7%, and the strain rate sensitivity coefficient increases to 0.1452. The results show that the decrease of grain size and texture density is the reason why EP-LSF can further improve the formability of AZ31B magnesium alloy. The changes in corrosion resistance were studied by scanning electron microscopy and electrochemical tests. The results show that after EP-LSF, the corrosion current density of AZ31 magnesium alloy decreased, and the electrochemical impedance increased, indicating that this method further improved the corrosion resistance.