Abstract
Precision castings of the Ti-6Al-4V alloy containing pore defects were hot isostatically pressed (HIP) in an attempt to improve the high cycle fatigue strength. Although all defects were healed, the fatigue strength was still low when compared to β-processed wrought material with a similar microstructure. Fatigue-crack initiation analysis, which included precision sectioning, indicated that early fatigue-crack initiation sites were related to relatively large α-platelet colonies and massive grain-boundary α(GBα) phase. Shear across the large colonies or along the GBα interfaces provided large initial cracks which resulted in the fatigue-life degradation. Large colonies and massive GBα developed in the HIP healed zones of the casting pores. In spite of the total HIP pore closure, the fatigue-strength improvement was small when compared to wrought material due to the coarse microstructure that developed in some locations during the HIP cycle. Large planar-shear initiation facets across several colonies were also observed. The multicolony faceted shear is the result of the Burgers relation between the colony orientations and increases the chance of early fatigue-crack inititation.
Article PDF
Similar content being viewed by others
Explore related subjects
Discover the latest articles, news and stories from top researchers in related subjects.Avoid common mistakes on your manuscript.
References
J. C. Chesnutt, C. G. Rhodes and J. C. Williams, ASTM STP 600 (American Society for Testing and Materials, Philadelphia, PA., 1976) p. 99.
D. Eylon and P. J. Bania, Met. Trans. A 9A (1978) 1273.
D. Eylon, J. A. Hall, C. M. Pierce and D. L. Ruckle, ibid 7A (1976) 1817.
D. Eylon and J. A. Hall, ibid 8A (1977) 981.
D. Shechtman and M. J. Blackburn, unpublished research (1975).
W. M. Parris and H. A. Russell, “Titanium Science and Technology”, Vol. 4, edited by R. I. Jaffee and H. M. Burte (Plenum, New York, 1973) p. 2219.
V. L. Hellmann and T. C. Tsarett, Air Force Materials Laboratory Report: AFML-TR-71-47, July (1971).
W. J. Barice, M. M. Allen and W. Grant, Air Force Materials Laboratory Report: AFML-TR-76-192, November (1976).
F. L. Parkinson, The Boeing Company Report No. FAA-SS-72-00, July (1972).
J. E. Coyne, “The Science, Technology and Application of Titanium”, edited by R. I. Jaffee and N. E. Promisel (Pregamon, New York, 1970) p. 97.
J. J. Lucas, “Titanium Science and Technology”, Vol. 3, edited by R. I. Jaffee and H. M. Burte (Plenum, New York, 1973) p. 2081.
D. Eylon and B. Strope, J. Mater. Sci. 14 (1979) 345.
D. Eylon and C. M. Pierce, Met. Trans. A 7A (1976) 111.
W. R. Kerr, D. Eylon and J. A. Hall, ibid 7A (1976) 1477.
D. Eylon and W. R. Kerr, “Fractographic Approach to Failure Analysis”, ASTM STP 645 (American Society for Testing and Materials, Philadelphia, PA., 1978) p. 235.
J. J. Grisik and D. B. Arnold, Interim Report IR162-2(III) on USAF Contract No. F33615-72-C-1381, Air Force Materials Laboratory, Wright-Patterson AFB, OH 45433, February (1973).
D. Eylon, Met. Trans. A. 10A (1979) 311.
D. Shechtman and D. Eylon, ibid 9A (1978) 1018.
G. T. Petrak, Air Force Materials Laboratory Report, AFML-TR-70-291, January (1971).
D. Eylon, Microscope 23 (1975) 133.
W. G. Burgers, Physica 1 (1934) 651.
J. C. Williams, “Titanium Science and Technology”, edited by R. I. Jaffe and H. M. Burte (Plenum, New York, 1973).
D. L. Davidson, ASTM STP 675 (American Society for Testing and Materials, Philadelphia, PA., 1979).
D. A. Meyn and G. Sandoz, Trans. Met. Soc. AIME 245 (1969) 1253.
D. A. Meyn, Met. Trans. 5 (1974) 2405.
J. Ruppen, P. Bhowal, D. Eylon and A. J. McEvely, ASTM STP 675 (American Society for Testing and Materials, Philadelphia, PA., 1979).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Eylon, D. Fatigue crack initiation in hot isostatically pressed Ti-6Al-4V castings. J Mater Sci 14, 1914–1922 (1979). https://doi.org/10.1007/BF00551032
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00551032