The investment casting and processing of cobalt-base and cobalt-bearing superalloys

To cope with the demands of engine manufacturers and other users, superalloys have been brought to work in service at temperatures which represent a very substantial fraction of their melting point. In addition to high temperature capability, they must exhibit mechanical strength, not only under static, but also under cyclic stressing conditions, and offer appropriate oxidation and corrosion resistance. This can only be achieved by tailoring their chemistry and processing conditions to the particular needs of the application under consideration. The evolution of component design and alloy chemistry, and some compositional effects and processing improvements in cast Ni-base superalloys are discussed.