Abstract
The shape of a fatigue crack tip as influenced by an air or a vacuum environment has been investigated in two stainless steels and an aluminum alloy. Under plane strain conditions and at crack growth rates in the Paris region, the crack tip opening displacement (CTOD) is much larger in vacuum than in air, a circumstance attributed to strain localization in air due to the presence of moisture and the absence of strain localization in vacuum. In type 304 stainless steel, a strain-induced transformation from austenite to martensite occurs at the crack tip, and the extent of this strain-induced transformation in type 304 stainless steel is consistent with the degree of blunting taking place at the crack tip as influenced by the environment. In air, the extent of transformation is a function of the ΔK level, and as a result, the crack opening level is found to differ in a ΔK decreasing test as compared to aAK increasing test. Fatigue striations are observed in air but are absent in vacuum. It is proposed that the greater extent of blunting in vacuum is responsible for the absence of striations in vacuum.
Similar content being viewed by others
References
A.J. McEvily, W. Zagrany, J.L. Gonzalez, and S. Matsuoka: inBasic Mechanisms of Fatigue of Metals, P. Lukas and J. Polak, eds., Elsevier, New York, NY, 1988, pp. 271–79.
R.P. Wei: in ASTM STP 675, J.T. Fong, ed., ASTM, Philadelphia, PA, 1979, pp. 816-30.
F.J. Bradshaw and C. Wheeler:Int. J. Fracture Mech., 1969, vol. 5, p. 255.
C.D. Beachem:Metall. Trans., 1972, vol. 3, pp. 437–51.
S.P. Lynch:Acta Metall., 1988, vol. 36, pp. 2639–61.
A. Onyewuenyi and J.P. Hirth:Metall. Trans. A, 1983, vol. 14A, pp. 259–69.
T. Zhang and P. Haasen:Phil. Mag. A, 1989, vol. 60, pp. 15–38.
N.M. Grinberg:Int. J. Fatigue, 1982, vol. 4, pp. 83–95.
Z. Nishiyama: inMartensitic Transformation, M.E. Fine, ed., Academic Press, New York, NY, 1978, pp. 433–40.
A.D. Pineau and R.M. Pelloux:Metall. Trans. A, 1974, vol. 5, pp. 1103–12.
C. Schuster and C. Alstetter:Metall. Trans. A, 1983, vol. 14A, pp. 2077–84.
Z. Mei and J.W. Morris, Jr.:Metall. Trans. A, 1990, vol. 21A, pp. 3137–52.
K. Ogura, Y. Miyoshi, and I. Nishikawa:Eng. Fracture Mech., 1986, vol. 25, pp. 31–46.
A.J. McEvily and Z. Yang:Metall. Trans. A, 1990, vol. 21A, pp. 2117–21.
M. Kikukawa, M. Jono, and K. Tanaka:Proc. 2nd Int. Conf. on Mech. Behavior of Materials, Special Volume, ASM, Metals Park, OH, 1978, pp. 254–77.
J.R. Rice: inFatigue Crack Propagation, ASTM STP 415, ASTM, Philadelphia, PA, I967, pp. 247–311.
B.D. Cullity:Elements of X-Ray Diffraction, Addison-Wesley, Reading, MA, 1956, pp. 269–72 and 411-19.
K. Minakawa and A.J. McEvily:Scripta Metall., 1981, vol. 15, pp. 633–36.
W. Elber:Eng. Fracture Mech., 1971, vol. 2, pp. 37–45.
A. Ohta and E. Sasaki:Acta Metall., 1972, vol. 20, pp. 657–60.
P. Neumann:Acta Metall., 1974, vol. 22, p. 1155.
G. Ming, P.S. Pao, and R.P. Wei:Metall. Trans. A, 1988, vol. 19A, pp. 1739–50.
M.O. Speidel: inCorrosion in Power Generating Equipment, M.O. Speidel and A. Atrens, eds., Plenum Press, New York, NY, 1984, pp. 85–132.
D.A. Meyn:Trans. ASM, 1968, vol. 61, pp. 42–48.
C. Laird: in ASTM STP 415, ASTM, Philadelphia, PA, 1967, p. 131.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
McEvily, A.J., Gonzalez Velazquez, J.L. Fatigue crack tip deformation Processes as Influenced by the Environment. Metall Trans A 23, 2211–2221 (1992). https://doi.org/10.1007/BF02646014
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF02646014