Investigation of Fatigue Crack Propagation in Nickel Superalloy Using Diffraction Contrast Tomography and Phase Contrast Tomography

Abstract:

Evaluation of superalloy component life in turbine engines requires a detailed understanding of how fatigue crack initiation and short crack propagation contribute to fatigue life. However most investigations have been carried out post-mortem and in two dimensions. New techniques are able to fully resolve cracks propagating in four dimensions (space and time), enabling characterisation of their local environments and allowing a much deeper understanding of fatigue mechanics. Nickel-based superalloys experiencing high cycle fatigue have shown a high sensitivity to microstructure during initiation and short crack propagation. Using high energy X-rays and the combination of Diffraction Contrast Tomography (DCT) and Phase Contrast Tomography (PCT), we followed a fatigue crack initiated from a Focused Ion Beam (FIB) milled notch at room temperature. Analyses have been carried out to fully characterise the crack and its environment. We tracked the evolution of the crack and interactions with the microstructure. Subsequently, post-mortem investigations have been carried out to corroborate results obtained from the tomographs and to provide more local information of fatigue crack propagation.

• Periodical: Advanced Materials Research (Volumes 891-892)
• Pages: 923-928
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.891-892.923
• Online since: March 2014
• Authors: Olivier M.D.M. Messé*, Joel Lachambre, Andrew King, Jean Yves Buffière, Cathie M.F. Rae
• Keywords: Crack Propagation, Fatigue, Image Processing, Nickel Superalloy, Tomography

References

[1] M.D. Sangid, H.J. Maier, and H. Sehitoglu. An energy-based microstructure model to account for fatigue scatter in polyscrystals. Journal of the Mechanics and Physics of Solids, 59: 595–609, (2011).

DOI: 10.1016/j.jmps.2010.12.014

[2] M.D. Sangid, H.J. Maier, and H. Sehitoglu. The role of grain boundaries on fatigue crack initiation – An energy approach. International Journal of Plasticity, (2010).

DOI: 10.1016/j.ijplas.2010.09.009

[3] J. Miao, T.M. Pollock, and J. Wayne Jones. Crystallographic Fatigue crack initiation in nickel-based superalloy René 88DT at elevated temperature. Acta Materialia, 57(20): 5964–5974, (2009).

DOI: 10.1016/j.actamat.2009.08.022

[4] A.J. Manning, D. Knowles, and C.J. Small. Nickel based superalloy. Patent US 2002/0041821 A1, United States Patent, (2002).

[5] J. Lachambre, A. Weck, J. Réthoré, J-Y. Buffière, J. Adrien. 3D Analysis of a Fatigue Crack in Cast Iron Using Digital Volume Correlation of X-ray Tomographic Images. Imaging Methods for Novel Materials and Challenging Applications, Volume 3, Conference Proceedings of the Society for Experimental Mechanics Series, 203-209, (2013).

DOI: 10.1007/978-1-4614-4235-6_28

[6] E. Ferrié, J. -Y. Buffière, and W. Ludwig. 3D Characterisation of the nucleation of a short fatigue crack at a pore in a cast Al alloy using high resolution synchrotron microtomography. International Journal of Fatigue, 27(10-12): 1215–1220, (2005).

DOI: 10.1016/j.ijfatigue.2005.07.015

[7] M. Herbig, A. King, P. Reischig, H. Proudhon, E.M. Lauridsen, J. Marrow, J.Y. Buffiere, and W. Ludwig. 3-D growth of a short fatigue crack within a polycrystalline microstructure studied using combined diffraction and phase-contrast X-ray tomography. Acta Materialia, 59: 590–601, (2011).

DOI: 10.1016/j.actamat.2010.09.063

[8] S. Birosca, J.Y. Buffière, M. Karadge, and M. Preuss. 3-D observations of short fatigue crack interaction with lamellar and duplex microstructures in a two-phase titanium alloy. Acta Materialia, 59: 1510–1522, (2011).

DOI: 10.1016/j.actamat.2010.11.015