Multiaxial Fatigue Analysis of a High Performance Nickel-Based Superalloy

Authors: P. Selva, B. Lorrain, J. Alexis, A. Seror, A. Longuet, C. Mary, F. Denard

Abstract:

Over the past four decades, the fatigue behavior of nickel-based alloys has been widely studied. However, in recent years, significant advances in the fabrication process leading to grain size reduction have been made in order to improve fatigue properties of aircraft turbine discs. Indeed, a change in particle size affects the initiation mode of fatigue cracks as well as the fatigue life of the material. The present study aims to investigate the fatigue behavior of a newly developed nickel-based superalloy under biaxial-planar loading. Low Cycle Fatigue (LCF) tests are performed at different stress ratios so as to study the influence of the multiaxial stress state on the fatigue life of the material. Full-field displacement and strain measurements as well as crack initiation detection are obtained using Digital Image Correlation (DIC) techniques. The aim of this presentation is first to provide an in-depth description of both the experimental set-up and protocol: the multiaxial testing machine, the specific design of the cruciform specimen and performances of the DIC code are introduced. Second, results for sixteen specimens related to different load ratios are presented. Crack detection, strain amplitude and number of cycles to crack initiation vs. triaxial stress ratio for each loading case are given. Third, from fractographic investigations by scanning electron microscopy it is found that the mechanism of fatigue crack initiation does not depend on the triaxial stress ratio and that most fatigue cracks initiate from subsurface carbides.

Keywords: Cruciform specimen, multiaxial fatigue, Nickelbased superalloy.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1100132

References:

[1] D. Fournier, A. Pineau, “Low cycle fatigue behavior of Inconel 718 at 298K and 823K”, Metallurgical Transactions A, vol. 8A, pp. 1095-1105, 1977.
[2] F. Alexandre, S. Deyber, A. Pineau, “Modelling the optimum grain size on the low cycle fatigue life of a Ni based superalloy in the presence of two possible crack initiation sites”, Scripta Materialia, vol. 50, pp. 25- 30, 2004.
[3] X.F. Ma, Z. Duan, H.J. Shi, R. Murai, E. Yanagisawa, “Fatigue and fracture behavior of nickel-based superalloy Inconel 718 up to the very high cycle regime”, Journal of Zhejiang Univ-Sci – Applied Physics & Engineering, vol. 10, pp. 727-737, 2010.
[4] V. Zerrouki, “Inconel 718 et tenue en fatigue oligocyclique. Influence de la microstructure et prédiction de la durée de vie”, Mémoire de DRT Génie des Matériaux, Université EVE, 2000.
[5] Y. Ohtake, S. Rokugawa, H. Masumoto, “Geometry determination of cruciform type specimen and biaxial tensile test of C/C composites”, Key Eng. Mater., vol. 3, pp. 151-154, 1999.
[6] S.B. Lin, J.L. Ding, H.M. Zbib, “Characterization of yield surfaces using balanced biaxial tests of cruciform plate specimens”, Scripta Metall. Mater., vol. 28, pp. 617-622, 1993.
[7] J.S. Welsh, D.F. Adams, “An experimental investigation of the biaxial strength of IM6/3501-6 carbon /epoxy cross-ply laminates using cruciform specimens”, Composites: Part A 33, vol. 6, pp. 829-839, 2002.
[8] M. Poncelet, G. Barbier, B. Raka, S. Courtin, R. Desmorat, J.C. Le- Roux, L. Vincent, “Biaxial high cycle fatigue of a type 304L stainless steel: cyclic strains end crack initiation detection by digital image correlation”, European Journal of Mechanics / A Solids, vol. 5, 2010.
[9] P. Terriault, K. Settouane, V. Brailovski, “Biaxial testing at different temperatures of cruciform Ti-Ni samples. In: Shape Memory and Superelastic Technologies”, California, 2003.
[10] A. Makinde, L. Thibodeau, K.W. Neale, “Development of an apparatus for biaxial testing for cruciform specimens”, Experimental mechanics, vol. 32, pp. 132-137, 1992.
[11] A. Scholz, C. Berger, A. Samir, R. Bardenheier, “Biaxiale TMFSimulation mit Kreuzproben zur Untersuchung des Kriechermüdungsverhaltens von hochtemperaturewerkstoffen. Weinheim”, Wiley, pp. 280-285, 2007.
[12] Abaqus Analysis User’s Manual v6.10.
[13] Aramis software. Gom Optical Measuring Techniques. http://www.gom.com/EN/index.html, 2006.
[14] S.P. Lynch, “Progression markings, striations, and crack-arrest markings on fracture surfaces”, Materials Sciences and Engineering A, 468-470, pp. 74-80, 2007.