ABSTRACT
The term superalloy is used to describe nickel-, iron-nickel-, and cobalt-based alloys generally used when operating temperatures are beyond 540°C (1000°F). Over the years, a large number of superalloys have been developed and employed in various applications, typically in gas turbine engines,
4.1 Fundamentals of Superalloys ................................................................................................ 151 4.1.1 Classi™cation and Composition ................................................................................ 152 4.1.2 Microstructure and Features ..................................................................................... 155
4.2 Properties of Superalloys ...................................................................................................... 159 4.2.1 Tribological Properties ............................................................................................. 160 4.2.2 Corrosion Resistance ................................................................................................ 166 4.2.3 Mechanical Properties .............................................................................................. 171
4.3 Development of Superalloys ................................................................................................. 177 4.3.1 Low-Carbon Stellite Alloy ....................................................................................... 178 4.3.2 Stellite 712 Composites ............................................................................................ 181 4.3.3 Stellite 21 Composites .............................................................................................. 185 4.3.4 Carbon Fiber-Reinforced Stellite Alloy Composites ................................................ 189 4.3.5 Ductility and Corrosion Resistance Improved Tribaloy Alloy ................................. 196 4.3.6 Oxidation and Hot-Wear Resistance-Enhanced Tribaloy Alloy ...............................202
