Enhanced Room Temperature Stretch Formability of AZ31B Magnesium Alloy Sheet by Laser Shock Peening

The applications of magnesium (Mg) and their alloys are often restricted by their poor formability at room temperature. Several strategies have been developed in recent years to enhance the formability of Mg alloys, such as grain refinement and texture weakening, either by alloying or processing. Laser shock peening (LSP) is an advanced laser-based surface processing method which has been utilized improve the surface hardness, fatigue performance, and corrosion resistance of Mg alloys. Recent studies show that LSP can bring significant texture weakening and grain refinement effect in Mg alloy, indicating its potential capability of enhancing the formability of Mg alloys. This research is to explore the applicability of LSP to improve the room temperature-stretch formability of Mg alloys. LSP experiments are carried out on an AZ31B Mg alloys. The microstructure before and after LSP are characterized by optical microscopy (OM) and electron backscattered diffraction (EBSD) microscopy. Erichsen tests are carried out to evaluate the stretch formability of Mg alloys. The results show that LSP can bring texture weakening and grain refinement effect simultaneously, resulting in the improved room temperature-stretch formability of Mg alloys.