Why does creep become a serious concern for metal parts in hot gas turbines?

In the context of materials testing, creep is the slow, progressive deformation of a material under prolonged stress. In hot gas turbines, this phenomenon is a critical concern because turbine components operate at extremely high temperatures to maximize thermodynamic efficiency.12

At elevated temperatures, the ductility of metals becomes a liability. Metals contain dislocations—structural defects within their crystal lattice—that allow the material to yield plastically under stress. While this ductility prevents immediate brittle fracture, high temperatures facilitate the movement of these dislocations, causing the metal to gradually flow and change dimensions over time.2

If a turbine blade or rotor undergoes excessive creep, it can lead to catastrophic mechanical failure or loss of operational clearance within the engine. Consequently, engineers must perform creep tests to measure deformation over time and predict the long-term structural integrity of these components under the intense heat and stress of turbine operation.12