Abstract: This invention relates to gadolinium-containing magnesium containing alloys, particularly those which possess high strength combined with corrosion resistance, and an optimized balance of strength and ductility. The described alloys consist of 2.0 to 5.0, preferably 2.3 to 4.6, at % in total of gadolinium and at least one of soluble heavy lanthanides and yttrium, wherein the ratio of the aggregate amount of soluble heavy lanthanides and yttrium to the amount of gadolinium is between 1.25:1 and 1.75:1, from 0 up to 0.3 at % of zirconium, preferably at least 0.03 at %, optionally with zinc, wherein when zinc is present the amount of zinc is such that the ratio of the weight of zinc to the weight of zirconium is preferably less than 2:1, all other lanthanides in an aggregate amount of less than at 0.2 at %, the balance being magnesium, with any other element being present in an amount of no more than 0.2 at %.