Abstract
The high temperature dwell fatigue crack growth behaviours of 30% cold-drawn and direct-aged ATI 718PlusTM were studied. This was compared to an annealed and direct aged variant of the same material. This was in order to rationalise the effects of cold work. Tests were conducted at 650 °C using different dwell times, in air and in relative vacuum, at R = 0.1. It was found that the cold-worked and direct-aged condition produced slower dwell fatigue crack growth rates in all tests. This has been linked to the larger elongated grain morphology and the dislocation structure retained after cold working. Increased crack tortuosity and roughness-induced crack closure are considered to enhance the cycle-dependent crack growth properties. Superior resistance to environmentally assisted intergranular failure is related to greater crack tip stress relaxation and more homogeneous grain boundary deformation.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
R.L. Kennedy, Allvac® 718plusTM, superalloy for the next forty years, in: Proc. Int. Symp. Superalloys Var. Deriv., 2005: pp. 1–14. https://doi.org/10.7449/2005/superalloys_2005_1_14.
M. Cemal, S. Cevik, Y. Uzunonat, F. Diltemiz, ALLVAC 718 PlusTM Superalloy for Aircraft Engine Applications, in: Recent Adv. Aircr. Technol., 2012. https://doi.org/10.5772/38433.
B.J. Bond, R.L. Kennedy, Evaluation of Allvac® 718PlusTM alloy in the cold worked and heat treated condition, in: Proc. Int. Symp. Superalloys Var. Deriv., 2005. https://doi.org/10.7449/2005/superalloys_2005_203_211.
W. Li, D. Terret, E. McDevitt, S. Ndoye, S. Gardner, Development of ati 718Plus® for high temperature high strength fastener applications, in: 8th Int. Symp. Superalloy 718 Deriv. 2014, 2014. https://doi.org/10.1002/9781119016854.ch40.
J. Bickford, Handbook of Bolts and Bolted Joints, 1998. https://doi.org/10.1201/9781482273786.
W.-D. Cao, R.L. Kennedy, Recommendations for Heat Treating Allvac® 718Plus® Alloy Parts, Monroe, NC, 2006.
A.A.N. Németh, D.J. Crudden, D.E.J. Armstrong, D.M. Collins, K. Li, A.J. Wilkinson, C.R.M. Grovenor, R.C. Reed, Environmentally-assisted grain boundary attack as a mechanism of embrittlement in a nickel-based superalloy, Acta Mater. 126 (2017) 361–371. https://doi.org/10.1016/j.actamat.2016.12.039.
E. Andrieu, G. Hochstetter, R. Molins, A. Pineau, Oxidation Mechanisms in Relation To High Temperature Fatigue, Superalloys 718,625,706 Var. Deriv. (1994).
H.Y. Li, J.F. Sun, M.C. Hardy, H.E. Evans, S.J. Williams, T.J.A. Doel, P. Bowen, Effects of microstructure on high temperature dwell fatigue crack growth in a coarse grain PM nickel based superalloy, Acta Mater. (2015). https://doi.org/10.1016/j.actamat.2015.02.023.
T.P. Gabb, J. Telesman, A. Banik, E. McDevitt, Use of slow strain rate tensile testing to assess the ability of several superalloys to resist environmentally-assisted intergranular cracking, in: 8th Int. Symp. Superalloy 718 Deriv. 2014, 2014. https://doi.org/10.1002/9781119016854.ch54.
D. Zheng, A. Rosenberger, H. Ghonem, Influence of prestraining on high temperature, low frequency fatigue crack growth in superalloys, Mater. Sci. Eng. A. (1993). https://doi.org/10.1016/0921-5093(93)90470-Y.
D. Zheng, H. Ghonem, Influence of prolonged thermal exposure on intergranular fatigue crack growth behavior in alloy 718 at 650 °C, Metall. Trans. A, Phys. Metall. Mater. Sci. 23 A (1992) 3169–3171. https://doi.org/10.1007/BF02646137.
X. Xie, C. Xu, G. Wang, J. Dong, W. Di Cao, R. Kennedy, TTT diagram of a newly developed nickel-base superalloy- Allvac® 718PlusTM, in: Proc. Int. Symp. Superalloys Var. Deriv., 2005. https://doi.org/10.7449/2005/superalloys_2005_193_202.
W. Di Cao, Solidification and solid state phase transformation of Allvac® 718PlusTM alloy, in: Proc. Int. Symp. Superalloys Var. Deriv., 2005. https://doi.org/10.7449/2005/superalloys_2005_165_177.
L. Viskari, Y. Cao, M. Norell, G. Sjöberg, K. Stiller, Grain boundary microstructure and fatigue crack growth in Allvac 718Plus superalloy, Mater. Sci. Eng. A. (2011). https://doi.org/10.1016/j.msea.2010.11.080.
J.L. Yuen, P. Roy, Effect of grain size on the near threshold fatigue crack propagation of a nickel base precipitation hardened superalloy, Scr. Metall. (1985). https://doi.org/10.1016/0036-9748(85)90257-1.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2020 The Minerals, Metals & Materials Society
About this paper
Cite this paper
Merrison, A., Li, H., Bowen, P., Li, W. (2020). High Temperature Dwell Fatigue Crack Growth in Cold-Worked and Direct-Aged 718PlusTM. In: Tin, S., et al. Superalloys 2020. The Minerals, Metals & Materials Series. Springer, Cham. https://doi.org/10.1007/978-3-030-51834-9_58
Download citation
DOI: https://doi.org/10.1007/978-3-030-51834-9_58
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-030-51833-2
Online ISBN: 978-3-030-51834-9
eBook Packages: Chemistry and Materials ScienceChemistry and Material Science (R0)