Abstract: The invention utilizes a hydrogen atmosphere during the heat treatment of an Al-Li alloy. The presence of such a reducing atmosphere prevents the reaction of surface lithium atoms with atmosphere components that would cause a diffusion and subsequent depletion of lithium atoms in the region near the surface. As a result, the present invention suppresses lithium loss and consequently prevents the formation of agglomerated lithium atom vacancies which would otherwise develop into microscopic metallic porosity. The prevention of such a condition maintains high fatigue resistance and corrosion resistance in association with metallic strength.