Materials Transactions, Vol.49 No.01 (2008) pp.144-150
© 2008 The Japan Institute of Metals

Fatigue Crack Initiation and Propagation in Lotus-Type Porous Copper

Hironori Seki, Masakazu Tane and Hideo Nakajima

We studied fatigue crack initiation and propagation in lotus-type porous copper with cylindrical pores aligned in one direction. For fatigue loadings in the direction parallel to the longitudinal axis of pores, stress field in the matrix is homogeneous. Therefore, slip bands are formed all over the specimen surface. On the other hand, for the perpendicular loadings, slip bands are formed only around pores in which stress highly concentrates. Since the localized slip bands form fatigue crack, fatigue fracture occurs even when the total plastic strain range is small. Stress field in the matrix of lotus copper affects the direction of crack propagation. For the parallel loadings, a crack propagates along a straight line as well as nonporous copper. On the other hand, for the perpendicular loading, a crack propagates along a path in which stress highly concentrates. Since stress highly concentrates around anomalously large pores, fatigue cracks are preferentially formed around the large pores and cracks propagate by crossing the large pores.

(Received 2007/9/3; Accepted 2007/10/22; Published 2007/12/5)

Keywords: porous metals, copper, fatigue, porosity, anisotropy, crack

PDF (Free)

Table of Contents

REFERENCES

1. L. J. Gibson and M. F. Ashby: Cellular Solids, 2nd ed., (Cambridge University Press, U.K., 1997) pp.1–51.
2. M. F. Ashby, A. Evans, N. A. Fleck, L. J. Gibson, J. W. Hutchinson and H. N. G. Wadley: Metal Foams, (Butterworth-Heineman Press, America, 2000) pp.3–5.
3. M. F. Ashby, A. Evans, N. A. Fleck, L. J. Gibson, J. W. Hutchinson and H. N. G. Wadley: Metal Foams, (Butterworth-Heineman Press, America, 2000) pp.40–49.
4. J. Banhart: Prog. Mater. Sci. 46 (2001) 559–632.
5. M. F. Ashby: Metall. Mater. Trans. A 14 (1983) 1755–1769.
6. H. Nakajima: Prog. Mater. Sci. 52 (2007) 1091–1173.
7. H. Nakajima, S. K. Hyun, K. Ohashi, K. Ota and K. Murakami: Colloids Surf. A: Physicochemical and Eng. Aspects. 179 (2001) 209–214.
8. H. Nakajima, T. Ikeda and S. K. Hyun: Adv. Eng. Mater. 6 (2004) 377–384.
9. S. K. Hyun, K. Murakami and H. Nakajima: Mater. Sci. Eng. A299 (2001) 241–248.
10. M. Tane, T. Ichitsubo, S. K. Hyun and H. Nakajima: J. Mater. Res. 20 (2005) 135–142.
11. M. Tane, T. Ichitsubo, H. Nakajima, S. K. Hyun and M. Hirao: Acta Mater. 52 (2004) 5195–5201.
12. M. Tane, T. Ichitsubo, M. Hirao, T. Ikeda and H. Nakajima: J. Appl. Phys. 96 (2004) 3696–3701.
13. H. Seki, M. Tane, M. Otsuka and H. Nakajima: J. Mater. Res. 22 (2007) 1331–1338.
14. E. Amsterdam, J. Th. M. De Hosson and P. R. Onck: Acta Mater. 54 (2006) 4465–4472.
15. J. Zhou and W. O. Soboyejo: Mater. Sci. Eng. A369 (2004) 23–35.
16. O. B. Olurin, K. Y. G. McCullough, N. A. Fleck and M. F. Ashby: Int. J. Fatigue 23 (2001) 375–382.
17. O. Schultz, A. D. Ligneris, O. Haider and P. Starke: Adv. Eng. Mater. 2 (2000) 215–218.
18. A.-M. Harte, N. A. Fleck and M. F. Ashby: Acta Mater. 47 (1999) 2511–2524.
19. Y. Sugimura, A. Rabiei, A. G. Evans, A. M. Harte and N. A. Fleck: Mater. Sci. Eng. A269 (1999) 38–48.
20. T. Ichitsubo, M. Tane, H. Ogi, M. Hirao, T. Ikeda and H. Nakajima: Acta Mater. 50 (2002) 4105–4115.
21. S. Suresh: Fatigue of materials, 2nd ed., (Cambridge University Press, U.K., 1998) pp.224–227.

© 2008 The Japan Institute of Metals
Comments to us : editjt@jim.or.jp