Abstract Magnesium alloyed with over 10-wt.pct. lithium can be transformed from its normal hexagonal-close packed α-phase into a single body-centered cubic β-phase. By adopting the crystal structure of lithium, ductility and formability of the new magnesium alloys can be improved. While magnesium is commonly cast to produce near-net shapes, the fusion welding of wrought magnesium alloy sheets with improved ductility may offer economical advantages to fabricate complex assemblies, particularly tailor welded blanks. In this preliminary research, microstructures and properties of gas-tungsten arc welds made on two magnesium-lithium alloys (7.5-wt.pct and 10.2-wt.pct lithium) are described and analyzed, as part of ongoing research on magnesium alloy joining and alloy development. Introduction The military, aerospace, and transportation industries have needs to reduce mass and improve efficiency without decreasing structural integrity. Magnesium is a potential material for many applications, because its low density is complemented by desirable features such as a high specific strength, good dampening characteristics, excellent castability, machineability, and recyclability