Abstract
We studied the effect of anisotropic pore morphology on the fatigue behavior and fracture surface of lotus-type porous copper, which was fabricated through unidirectional solidification in pressurized hydrogen and argon atmospheres. The fatigue strength at finite life is closely related to the pore morphology. The fatigue strength decreases with increasing porosity, and the strength depends on applied-stress direction. The fatigue life is the longest in the direction parallel to the longitudinal axis of cylindrical pores. The fatigue strength at finite life is proportional to the ultimate tensile strength and can be expressed by a simple power-law formula. Anisotropic pores affect the fracture surface of lotus copper; crack-initiation site depends on applied-stress direction, and the anisotropic shape pores affect the direction of crack propagation and final fracture surface.
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M.F. Ashby, A. Evans, N.A. Fleck, L.J. Gibson, J.W. Hutchinson, and H.N.G Wadley: Metal Foams (Butterworth-Heineman Press/Elsevier Science, Burlington, MA, 2000).
J. Banhart: Manufacture, characterisation and application of cellular metals and metal foams. Prog. Mater. Sci. 46, 559 (2001).
M.F. Ashby: The mechanical-properties of cellular solids. Metall. Mater. Trans. A 14, 1755 (1983).
L.J. Gibson and M.F. Ashby: Cellular Solids2nd ed. (Cambridge University Press, U.K., 1997).
H. Nakajima, S.K. Hyun, K. Ohashi, K. Ota, and K. Murakami: Fabrication of porous copper by unidirectional solidification under hydrogen and its properties. Colloids Surf., A 179, 209 (2001).
H. Nakajima, T. Ikeda, and S.K. Hyun: Fabrication of lotus-type porous metals and their physical properties. Adv. Eng. Mater. 6, 377 (2004).
S.K. Hyun and H. Nakajima: Anisotropic compressive properties of porous copper produced by unidirectional solidification. Mater. Sci. Eng. A340, 258 (2003).
M. Tane, T. Ichitsubo, S.K. Hyun, and H. Nakajima: Anisotropic yield behavior of lotus-type porous iron: Measurements and micromechanical mean-field analysis. J. Mater. Res. 20, 135 (2005).
M. Tane, T. Ichitsubo, H. Nakajima, S.K. Hyun, and M. Hirao: Elastic properties of lotus-type porous iron: Acoustic measurement and extended effective-mean-field theory. Acta Mater. 52, 5195 (2004).
Y. Sugimura, J. Meyer, M.Y. He, H. Bart-Smith, J. Grenstedt, and A.G. Evans: On the mechanical performance of closed cell Al alloy foams. Acta Mater. 45, 5245 (1997).
J. Zhou and W.O. Soboyejo: Compression-compression fatigue of open cell aluminum foams: macro-/micro- mechanisms and the effects of heat treatment. Mater. Sci. Eng. A369, 23 (2004).
O.B. Olurin, K.Y.G McCullough, N.A. Fleck, and M.F. Ashby: Fatigue-crack propagation in aluminium alloy foams. Int. J. Fatigue 23, 375 (2001).
A.M. Harte, N.A. Fleck, and M.F. Ashby: Fatigue failure of an open cell and a closed cell aluminium alloy foam. Acta Mater. 47, 2511 (1999).
Y. Sugimura, A. Rabiei, A.G. Evans, A.M. Harte, and N.A. Fleck: Compression fatigue of a cellular Al alloy. Mater. Sci. Eng. A269, 38 (1999).
H. Seki, S. Yamazaki, M. Otsuka, M. Tane, S.K. Hyun, and H. Nakajima: Effect of porosity on fatigue strength of lotus-type porous copper. Mater. Sci. Forum 510, 966 (2006).
S.K. Hyun and H. Nakajima: Effect of solidification velocity on pore morphology of lotus-type porous metals fabricated by unidirectional solidification. Mater. Lett. 57, 3149 (2003).
T. Ichitsubo, M. Tane, H. Ogi, M. Hirao, T. Ikeda, and H. Nakajima: Anisotropic elastic constants of lotus-type porous copper: Measurements and micromechanics modeling. Acta Mater. 50, 4105 (2002).
H. Onishi, S.K. Hyun, and H. Nakajima: Measurement of pore length of lotus-type porous nickel, in Porous Metals and Metal Foaming Technology, edited by H. Nakajima and N. Kanetake (The Japan Institute of Metals, Sendai, Japan, 2006), p. 423.
S. Suresh: Fatigue of Materials2nd ed. (Cambridge University Press, UK, 1998).
S.K. Hyun, K. Murakami, and H. Nakajima: Anisotropic mechanical properties of porous copper fabricated by unidirectional solidification. Mater. Sci. Eng. A299, 241 (2001).
T.L. Gerber and H.O. Fuchs: Analysis of non-propagating cracks in notched parts with compressive mean stress. J. Mater. 3, 359 (1968).
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Seki, H., Tane, M., Otsuka, M. et al. Effects of pore morphology on fatigue strength and fracture surface of lotus-type porous copper. Journal of Materials Research 22, 1331–1338 (2007). https://doi.org/10.1557/jmr.2007.0164
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DOI: https://doi.org/10.1557/jmr.2007.0164