This age hardenable nickel-cobalt base alloy that has a unique combination of properties: ultra- high strength, toughness, ductility and outstanding corrosion resistance. The alloy resists corrosion in hydrogen sulfide, salt water and other chloride solutions with excellent resistance to crevice and stress corrosion cracking in sea water and other hostile environments. Suitable where a high combination of strength, high modulus values and good corrosion resistance are required.