Investigation on material degradation during tip-rub events

Minimising the clearance between the blade tip and casing is important in modern aeroengines to improve efficiency (by reducing fuel consumption). The inclusion of sacrificial materials in the casing provides a 'soft' material should an incursion occur. Such events lead to heat generation and a complex multiaxial stress state (combinations of centrifugal loads and frictional loading), which can result in degradation in the form of wear and microstructural changes in the material of the blade and liner and, therefore, a reduced capability to endure service loads and temperatures, or any future incursion events. The proposed work will provide fundamental understanding through both experimental and modelling approaches, of the effect of incursion events on the microstructural and mechanical properties of the blade tip and liner materials and will assist in assessing the effects on the remaining life and future behaviour, leading to improved design and lifing rules for incursion events.