Oxidation resistant magnesium alloy

A magnesium alloy characterized by having good resistance to oxidation in the molten state, good corrosion resistance and good tensile strength, said alloy consisting essentially of up to 12 percent of aluminum, up to 30 percent of zinc, up to 1.5 percent of silicon, from 0.04 percent to 0.15 percent of manganese, and a given amount of dissolved beryllium, the given amount constituting from 0.0025 percent to 0.0125 percent of the alloy, balance essentially magnesium, wherein the manganese content of the alloy is sufficiently low that it does not prevent dissolution of the given amount of beryllium, wherein the relative proportions of aluminum and zinc are such that the alloy is castable and ductile, and is not subject to hot cracking and wherein the alloy contains at least 2 percent of aluminum or zinc in an amount greater than 3 percent and sufficiently high that the alloy has the degree of fluidity in the molten state requisite for die casting.