Surface roughness effects of the fatigue behavior of as machined inconel718

Hamid Javadi (1) , Walid Jomaa (1, 2) , Damien Texier (1) , Myriam Brochu (3) , Philippe Bocher (1)

1 ETS - Ecole de Technologie Supérieure [Montréal]
2 ULaval - Université Laval [Québec]
3 EPM - École Polytechnique de Montréal

Surface finish of machined components plays a key role in their life performance. The aim of this research is to investigate the effect of different roughness parameters on high cycle fatigue behavior of Inconel718. Rotating bending fatigue tests have been performed on Inconel718 specimens with various surface roughnesses produced by turning. Height and amplitude distribution roughness parameters were investigated. Statistical analyses show that a valley material component (Mr2), as one of the amplitude distribution parameters, is the most relevant parameter for the high cycle fatigue life of machined specimens. Observations conducted at the surface of broken specimens gage length, have shown the impact of surface roughness and residual stresses on the crack propagation mode. When the roughness increases, valleys were shown to be deeper and larger, leading to a higher Mr2 value and an increase of stress concentration.

Mots clés: Superalloy; Machining; Lathe-turning; Inconel 718; Superalloys nickel-based; Turning; Fatigue Crack Initiation; Roughness effect; Fatigue and cracks; Fatigue behaviour; Surface integrity; Fatigue; Fatigue behavior

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

Hamid Javadi, Walid Jomaa, Damien Texier, Myriam Brochu, Philippe Bocher. Surface roughness effects of the fatigue behavior of as machined inconel718. Solid State Phenomena, 2016, 258, pp.306 - 309. ⟨10.4028/www.scientific.net/SSP.258.306⟩. ⟨hal-01823510⟩