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The Role of Local Microstructure on Small Fatigue Crack Propagation in an α + β Titanium Alloy, Ti-6Al-2Sn-4Zr-6Mo

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Abstract

Microstructural origins of the variability in fatigue lifetime observed in the high- and very-high-cycle fatigue regimes in titanium alloys were explored by examining the role of microstructural heterogeneity (neighborhoods of grains with similar crystallographic orientations or microtexture) on the initiation and early growth of fatigue cracks in Ti-6246. Ultrasonic fatigue of focused ion beam (FIB) micronotched samples was used to investigate long lifetime (107 to 109) behavior for two microstructural conditions: one with microtexture and one without microtexture. For specimens containing notches of nominally 20 μm in length, fatigue crack initiation in the microtextured material was most likely to occur from notches placed in neighborhoods with a microtexture favorably oriented for easy basal slip. Initiation lifetimes in the untextured material with similar sized notches were, on average, slightly greater than those for the microtextured condition. In both materials, the crack-initiation lifetime from micronotches of length 2c > 20 μm was a very small fraction (<1 pct) of the measured fatigue lifetime for unnotched specimens. Furthermore, in the microtextured condition, small fatigue crack propagation rates did not correlate with the microtextured regions and did not statistically differ from average small crack growth rates in the untextured material. As the micronotch size was reduced below 20 μm, fatigue crack initiation was controlled by microstructure rather than by FIB-machined defects. Finally, predictions of the fraction of life consumed in small and long fatigue crack growth from preexisting cracks nominally equivalent in size to the micronotches was compared with the measured fatigue life of unnotched specimens. The predicted range of lifetimes when factoring in the experimentally observed variability in small fatigue crack growth, only accounted for 0.1 pct of the observed fatigue lifetime variability. These findings indicate that in the high-and very-high-cycle fatigue regimes, fatigue life is dominated by crack initiation and that the variation in the initiation lifetime is responsible for the observed variation in total fatigue life.

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References

  1. C.J. Szczepanski, S.K. Jha, J.M. Larsen, and J.W. Jones: Metall. Mater. Trans. A, 2008, vol. 39A, pp. 2841–51.

    Article  CAS  Google Scholar 

  2. C.J. Szczepanski: Ph.D. Dissertation, University of Michigan, Ann Arbor, MI, 2008.

  3. M.G. Glavicic, B.B. Bartha, S.K. Jha, and C.J. Szczepanski: Mater. Sci. Eng. A, 2009, vols. A513–14, pp. 325–28.

  4. J.A. Hall: Int. J. Fatigue., 1997, vol. 31, pp. S23–S37.

    Article  Google Scholar 

  5. G. Lütjering: Mater. Sci. Eng. A, 1998, vol. A243, pp. 32–45.

    Google Scholar 

  6. G. Luetjering and M. Peters: EPRI CS 2933. Project 1266-1. Final Report – Electric Power Research Institute, Palo Alto, CA, 1983.

  7. F. Larson and A. Zarkades: MCIC Report - MCIC·74-20 – Metals and Ceramics Information Center, Columbus, OH, 1974.

  8. S.K. Jha, M.J. Caton, and J.M. Larsen: Mater. Sci. Eng. A, 2007, vols. A468–70, pp. 23–32.

  9. L. Christodoulou and J.M. Larsen: JOM, 2004, pp. 15–19.

  10. S.K. Jha, J.M. Larsen, A.H. Rosenberger, and G.A. Hartman: Scripta Mater., 2003, vol. 48, pp. 1637–42.

    Article  CAS  Google Scholar 

  11. D.L. Davidson, R.G. Tryon, M. Oja, R. Matthews, and K.S.R. Chandran: Metall. Mater. Trans. A, 2007, vol. 38A, pp. 2214–25.

    Article  CAS  Google Scholar 

  12. V. Sinha, J.E. Spowart, M.J. Mills, and J.C. Williams: Metall. Mater. Trans. A, 2006, vol. 37A, pp.1507–18.

    Article  CAS  Google Scholar 

  13. K. LeBiavant, S. Pommier, and C. Prioul: Fatig. Fract. Eng. Mater. Struct., 2002, vol. 25, pp. 527–45.

    Article  CAS  Google Scholar 

  14. F. Bridier, P. Villechaise, and J. Mendez: Acta Mater., 2008, vol. 56, pp. 3951–62.

    Article  CAS  Google Scholar 

  15. I. Bantounas, D. Dye, and T.C. Lindley: Acta Mater., 2009, vol. 57, pp. 3584–95.

    Article  CAS  Google Scholar 

  16. M. Brogdon and A.H. Rosenberger: Superalloys 2008, R.C. Reed, K.A. Green, P. Caron, T.P. Gabb, M.G Fahrmann, E.S. Huron, and S.A. Woodard, eds., TMS, Warrendale, PA, 2008, pp. 583–88.

  17. S.K. Jha and J.M. Larsen: VHCF4, J.E. Allison, J.W. Jones, J.M. Larsen, and R. Ritchie, eds., TMS, Warrendale, PA, 2007, pp. 385–96.

  18. M. Peters, A. Gysler, and G. Lutjering: Metall. Trans. A, 1984, vol. 15A, pp. 1597–1605.

    CAS  Google Scholar 

  19. A.W. Bowen: Acta Metall., 1975, vol. 23, pp. 1401–09.

    Article  CAS  Google Scholar 

  20. A.P. Woodfield, M.D. Gorman, R.R. Corderman, J.A. Sutliff, and B. Yamrom: Titanium ’95: Science and Technology, P.A. Blenkinsop, W.J. Evans, and H.M. Flower, eds., Institute of Materials, Birmingham, UK, 1996, pp.1116–23.

  21. I. Bantounas, T.C. Lindley, D. Rugg, and D. Dye: Acta Mater., 2007, vol. 55, pp. 5655–65.

    Article  CAS  Google Scholar 

  22. T. Zhai, A.J. Wilkinson, and J.W. Martin: Acta Mater., 2000, vol. 48, pp. 4917–27.

    Article  CAS  Google Scholar 

  23. T. Zhai: Proc. from Materials Solutions Conf., 2001, ASM International, Indianapolis, IN, pp. 83–91.

  24. M. Marx, W. Schaef, and H. Vehoff: Proced. Eng., 2010, vol. 2, pp. 163–71.

    Article  Google Scholar 

  25. U. Krupp, W. Floer, J. Lei, Y. Hu, H. Christ, A. Schick, and C. Fritzen: Philos. Mag. A, 2002, vol. 82, pp. 3321–32.

    CAS  Google Scholar 

  26. Y. Saleh and H. Margolin: Metall. Trans. A, 1983, vol. 14A, pp. 1481–86.

    CAS  Google Scholar 

  27. E.B. Shell and S.L. Semiatin: Metall. Mater. Trans. A, 1999, vol. 30A, pp. 3219–29.

    Article  CAS  Google Scholar 

  28. T.R. Bieler and S.L. Semiatin: Int. J. Plast., 2002, vol. 18, pp. 1165–89.

    Article  CAS  Google Scholar 

  29. J.M. Larsen, J.R. Jira, and K.S. Ravichandran: STP 1149, ASTM, 1992, Philadelphia, PA, pp. 57–80.

  30. Q. Feng, Y. Picard, H. Liu, S. Yalisove, G. Mourou, and T.M. Pollock: Scripta Mater., 2005, vol. 53, pp. 511–16.

    Article  CAS  Google Scholar 

  31. A. Shyam, C. Torbet, S.K. Jha, J. Larsen, M. Caton, C. Szczepanski, T.M. Pollock, and J.W. Jones: Superalloys 2004, K. Green, T.M. Pollock, H. Harada, T. Howson, R. Reed, J. Schirra, and S. Walston, eds., TMS, Warrendale, PA, pp. 259–68.

  32. X. Zhu: Ph.D. Dissertation, University of Michigan, Ann Arbor, MI, 2007.

  33. J. Orloff, M. Utlaut, and L. Swanson: High Resolution Focused Ion Beams: FIB and its Applications, Kluwer Academic/Plenum Publishers, New York, NY, 2003.

    Google Scholar 

  34. J. Newman and I. Raju: Eng. Fract. Mech., 1981, vol. 15, pp. 185–92.

    Article  Google Scholar 

  35. K.S. Chan and J. Lankford: Acta Metall., 1988, vol. 36, pp. 193–206.

    Article  Google Scholar 

  36. S. Suresh and R.O. Ritchie: Int. Mater. Rev., 1984, vol. 29, pp. 445–76.

    Google Scholar 

  37. C.J. Szczepanski, A. Shyam, S.K. Jha, J.M. Larsen, C.J. Torbet, S.J. Johnson, and J.W. Jones: Materials Damage Prognosis, J.M. Larsen, L. Christodoulou, J.R. Calcaterra, M.L. Dent, M.M. Deriso, W.J. Hardman, J.W. Jones, and S.M. Russ, eds., TMS, Warrendale, PA, 2005, pp. 315–20.

  38. J.M. Larsen: unpublished research, 1992.

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Acknowledgments

Financial support from the AFOSR Metallic Materials Program (Project #F49620-03-1-0069) and the AFOSR Structural Mechanics Program (Dr. David Stargel, Project #2302DR1P) are gratefully acknowledged. One author (CJS) would like to acknowledge funding from the STEP program at the AFRL Materials and Manufacturing Directorate. Technical assistance from C. Torbet of the University of Michigan is appreciated. The experimental assistance of Mr. M. Eric Burba and Mr. Benjamin Briskin, both affiliated with AFRL, is also appreciated.

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Authors and Affiliations

  1. Air Force Research Laboratory, Materials and Manufacturing Directorate, AFRL/RXLM, Wright-Patterson Air Force Base, OH, 45433, USA

    C. J. Szczepanski (Materials Research Engineer)

  2. Universal Technology Corporation, Dayton, OH, 45432, USA

    S. K. Jha (Research Scientist)

  3. Air Force Research Laboratory, Materials and Manufacturing Directorate, AFRL/RX, Wright-Patterson Air Force Base, OH, 45433, USA

    J. M. Larsen (Senior Scientist)

  4. Materials Science and Engineering Department, University of Michigan, Ann Arbor, MI, 48109, USA

    J. W. Jones (Arthur F. Thurnau Professor)

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  1. C. J. Szczepanski
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Correspondence to C. J. Szczepanski.

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Manuscript submitted September 30, 2011.

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Szczepanski, C.J., Jha, S.K., Larsen, J.M. et al. The Role of Local Microstructure on Small Fatigue Crack Propagation in an α + β Titanium Alloy, Ti-6Al-2Sn-4Zr-6Mo. Metall Mater Trans A 43, 4097–4112 (2012). https://doi.org/10.1007/s11661-012-1228-z

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