Creep Failure in Aeroengine Components

This chapter focuses on the creep failure of aeroengine components. This topic has gained importance over the past decades as the high-temperature performance of aeroengine components often dictates engine performance. Ni-based superalloys were developed specifically for high-temperature aerospace applications and are used in the hottest part of the engine, where the leading cause of failure is creep. It is therefore useful to investigate the creep behavior of Ni-based superalloys. Creep in Ni-based superalloys usually manifests through different mechanisms, depending on the temperature and stress of their environment. These creep mechanisms are greatly affected by dislocation activity and microstructure evolution. The γ′ phase plays a very important role, especially in single-crystal superalloys, as it is the main strengthening phase. The coarsening of γ′ precipitates and the rafting process are some of the main microstructural mechanisms that lead to creep failure. Apart from γ′ precipitates, carbides and Topologically Close-Packed (TCP) phases can also promote nucleation and propagation of microvoids, which is detrimental to creep properties. An overview of the creep failure mechanisms, as well as the influence of time and temperature on creep failure, is given in this chapter, followed by a brief discussion of methods to enhance creep performance, such as material, manufacturing, and post-processing techniques.