Abstract: A stabilization heat treatment for a class of wrought cobalt alloys is described. The heat treatment produces a useful combination of initial ductility, so as to permit fabrication of intricate parts, and adequate ductility even after long term exposure at elevated temperatures as, for example, that exposure encountered in gas turbine service. The heat treatment consists of a solution treatment performed at elevated temperatures followed by two aging steps at lower temperatures. The nominal alloy composition is 22.5% chromium, 4.25% aluminum, 15% (nickel+iron), 3% (tantalum+columbium), 10% (tungsten+molybdenum), 1.25% hafnium, 0.05% yttrium, 0.35% carbon, balance essentially cobalt.