Magnesium alloy and process for producing the same

A magnesium alloy having excellent strength and elongation at high temperatures and further having excellent creep characteristics at high temperatures. Also provided is a process for producing the alloy. In producing the magnesium alloy, a magnesium alloy containing yttrium and samarium in respective specific amounts is cast and the resultant cast is subjected to a solution heat treatment, subsequently hot working, and then an aging treatment, thereby reducing the average crystal grain diameter of the structure. In addition, the amounts of the yttrium and samarium in solution in the magnesium matrix are balanced with the number of precipitate particles of a specific size in the crystal grains. The magnesium alloy thus obtained has excellent strength and elongation at high temperatures and further having excellent creep characteristics at high temperatures.