William Harrison

By Mark Whittaker, Veronica Gray and William Harrison

Lifing of components which are likely to be subject to high temperature creep deformation is a critical area to a range of industries, particularly power generation and aerospace. In particular, extrapolation of short term data to predict long-term allowable creep stresses is an area of significant importance, since no appropriate method of accelerating tests has been discovered. Traditional methods for extrapolation are mainly based around power law type equations that have historically formed the basis of creep mechanism understanding. The current chapter however, seeks to offer alternative approaches in the field, particularly emphasising the need to link lifing approaches to observable micro-mechanical behaviour.

Part of the book: Creep

By William Harrison, Mark Whittaker and Veronica Gray

There are many applications where the combination of stress and elevated temperature require creep to be considered during the design process. For some applications, an evaluation of rupture life for given conditions is sufficient, however, for components such as those in gas turbine aeroengines, the accumulation of creep strain over time and the effect this has on other phenomena, such as high-temperature fatigue must be considered. In this chapter, modern creep curve modelling methods are applied to alloys used in gas turbine applications over a wide range of test conditions. Also, different creep hardening modelling methods are discussed along with their application to transient creep showing the deficiencies of simplistic models. Models are related to micromechanical properties where possible, and creep damage models are evaluated and applied to different applications using finite element analysis (FEA).

Part of the book: Creep