Impact of Residual Stresses on the Fatigue Behavior of a Nickel-Based Superalloy

Amélie Morançais (1) , Mathieu Fèvre (2) , Pascale Kanoute (1, 3) , Serge Kruch (4) , Manuel François (3)

1 ONERA - The French Aerospace Lab [Châtillon]
2 LEM - ONERA - CNRS - Laboratoire d'étude des microstructures [Châtillon]
3 LASMIS - Laboratoire des Systèmes Mécaniques et d'Ingénierie Simultanée
4 ONERA - The French Aerospace Lab [Palaiseau]

Aircraft engine components are subjected, voluntarily or not, to the influence of residual stresses (RS). These RS may evolve in service conditions and may have an influence on fatigue life of the component. This paper presents a method to take into account the RS and their relaxation in a finite element calculation to obtain the fatigue life. This method is applied to a representative high-pressure turbine disk specimen made of N18 Nickel-based superalloy. Firstly, residual stresses are measured using X-Ray diffraction technique on the surface and the thickness of specimens. The influence of different surface finishing processes on the intensity and distribution of RS is compared to as-received specimen. Then, using the experimental profile as an initial state, a fatigue life analysis is performed (on fatigue specimen) by applying a multiaxial extension of the Smith-Watson-Topper model. Numerical and experimental results are discussed in detail and it appears that residual compressive stresses have almost no influence for high strain range but they improve the fatigue life for lower ranges.

Domaines: Mécanique des matériaux [physics.class-ph]

Amélie Morançais, Mathieu Fèvre, Pascale Kanoute, Serge Kruch, Manuel François. Impact of Residual Stresses on the Fatigue Behavior of a Nickel-Based Superalloy. Materials Science Forum, 2013, 768-769, pp.747-754. ⟨10.4028/www.scientific.net/MSF.768-769.747⟩. ⟨hal-02278279⟩