ABSTRACT
This chapter focuses on casting alloys. Two groups of alloys are considered: single-crystal and polycrystalline state of nickel superalloys and Ni3Al single-crystal intermetallic alloys. All of these alloys are used for manufacturing of gas turbine blades. Results of the study on the influence of severe deformations on the structure and properties of the nickel superalloys are presented in this chapter. Nickel superalloys used in aircrafts operate at the highest levels of stresses and temperatures (up to 1200°C). Also, nickel superalloys used in electric power stations operate at lower temperatures (800-900°C), because of that the nickel gas turbine blades may also be under extreme stresses when the turbine power increases. The main factor for a long trouble-free operation time of the turbine blades is their structural and phase stability at high temperatures. In this chapter, we present the results of the analysis of the gas turbine blade failure under external effects (high temperature, rotation, vibration). We also found that a magnetic non-destructive testing of the structure state of the working nickel gas turbine blade may be used in the industrial monitoring process of its operation, maintenance and failure.
