Crack Tip Dislocations and its Shielding Effect


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Two dimensional simulations of discrete dislocation dynamics were carried out to clarify a shielding effect due to dislocations at a crack tip. The configuration of dislocations around the crack tip was calculated under the conditions of mode I tensile load at high temperatures. The stress field around the crack tip due to dislocations was found to be compressive, accommodating mode I stress intensity at the crack tip. In order to experimentally confirm the stress accommodation, infrared photoelastic observation was also performed in a specimen pre-deformed at high temperatures. The experimental result is in good agreement with a simulated infrared photoelastic image derived from the stress field calculated.



Materials Science Forum (Volumes 561-565)

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Edited by:

Young Won Chang, Nack J. Kim and Chong Soo Lee




M. Tanaka et al., "Crack Tip Dislocations and its Shielding Effect", Materials Science Forum, Vols. 561-565, pp. 1833-1836, 2007

Online since:

October 2007




[1] J.R. Rice, R. Thomson, Phil. Mag. 29 (1974) 73-97.

[2] S. Majumdar, S.J. Burns, Acta. Met., 29 (1981) 579-588.

[3] I. -H. Lin, R. Thomson, Acta. Met., 34 (1986) 187-206.

[4] R. Thomson, Scripta Metal., 20 (1986) 1437-1476.

[5] J. Weertman, Acta Metall., 26 (1978) 1731-1738.

[6] C. St. John, Phil. Mag., 32 (1975) 1193-1212.

[7] P. B. Hirsch, S.G. Roberts, J. Samuels, Proc. R. Soc. Lond. A, 421 (1989) 25- 53.

[8] A. George, G. Michot, Mater. Sci. Eng., A164 (1993) 118 - 134.

[9] P.B. Hirsch, S.G. Roberts, Phil. Trans. R. Soc. Lond. A 355 (1997) 1991-(2002).

[10] K. Higashida, N. Narita, K. Matsunaga, R. Onodera, Phys. Stat. Sol. (a), 149 (1995) 429-443.

[11] K. Higashida, N. Narita, Mater. Trans., 42 (2001) 33-40.

[12] A. Hartmaier, P. Gumbsch, Philo. Mag., A82 (2002) 3187-3200.

[13] M. Tanaka, K. Higashida, T. Haraguchi, Mat. Sci. Eng., A387-389 (2004) 433-437.

[14] H.W. Schadler, Acta metal., 12 (1964) 861-871.