A Review on Characterization, Classifications, and Applications of Super Alloys

Abstract

Over the past 50 years, the development of high-temperature engineering alloys had been a primary driver of increased operating temperatures for material used in gas turbine engines. This has resulted in dramatic improvements in both their power and efficiency. It has been reported that a 170 ℃ increase in the engine operating temperature improves an engine‘s thrust by 5 % and the efficiency by 1%. Materials used for turbine blades and vanes found in the hot sections of gas turbine engines must endure extremely hot engine gases, an oxidative and hot corrosive environment, large centrifugal loads, and high-velocity foreign object impacts. New blade/van materials must therefore possess a balance of high-temperature strength, toughness, oxidation, and corrosion resistance.

Superalloys are the major class of materials used for the high-temperature components in the fact that they are the only commercially available materials that retain their mechanical and corrosion / oxidation-resistant properties at high temperatures (up to 0.9 Tm). There are three main classes of superalloys: nickel-base superalloys, cobalt-base superalloys, and iron-base superalloys. Superalloys are currently used in many high-temperature fields from gas turbines used in aircraft, marine, and industrial applications, to space vehicles, nuclear reactors, steam power plants, and petrochemical equipment. The largest consumer of superalloys today the aircraft gas turbine engine industry. In this review, each group of superalloys has briefly presented its key characteristics and chemical compositions. Lastly, their manufacturing uses were illustrated.