Laser processing of Mg-10Li-3Al-3Zn alloy： Part Ⅰ – Microstructure and properties of laser welded joints

Abstract

MBLS10A-200 magnesium-lithium (Mg-Li) alloy is a novel ultralight material, with the density, tensile strength and elongation rate of 1.5 g/cm3, 160 MPa and 60%, respectively. At present, the material is increasingly widely applied in structures with complex shapes of various fields such as aeronautics, astronautics and electronic engineering. At present, the industrial circle has put forward increasingly urgent demand for the welding technique of MBLS10A-200 alloy and the protection technology for corrosion resistance of the welded joints of the alloy. However, related research is rarely reported. Laser welding of MBLS10A-200 Mg-Li alloy with 5 mm in thickness was studied to further obtain the butt joint, with the elongation rate of about 54% and the same strength as base metal (BM). Moreover, the corrosion resistance of laser welded joint was detected by using electrochemistry method. During the experiment, it can be found that the corrosion resistance of metals in the welded seam zone (WSZ) was far higher than that of the BM. The corrosion current density of metals in WSZ was about 10-5 A/cm2, which declined by two orders of magnitude compared with BMs which were about 10-7 A/cm2 and the charge transfer resistance of welded seam zone increased by 4.8 times compared with BMs.