Dynamic Embrittlement - Diffusion-Induced Intergranular Cracking

Abstract:

The present paper is about dynamic embrittlement as a generic damage mechanism. It involves grain-boundary diffusion of an embrittling species at elevated temperatures under the influence of mechanical stress. The embrittling species, either coming from the material itself or from the environment, reduces the grain-boundary cohesion and, hence, causes time-dependent intergranular fracture. Evidence of the technical significance of dynamic embrittlement is given by two examples, stress-relief cracking in steels and hold-time cracking during low-cycle-fatigue loading of nickel-base superalloys. There is an obvious relationship between the grain-boundary structure and the local susceptibility to dynamic embrittlement. This was proven by mechanical experiments on bicrystals and grain-boundary-engineering-type-processed specimens.

• Periodical: Defect and Diffusion Forum (Volumes 258-260)
• Pages: 192-198
• DOI: https://doi.org/10.4028/www.scientific.net/DDF.258-260.192
• Online since: October 2006
• Authors: Ulrich Krupp
• Keywords: Alloy 718, Dynamic Embrittlement, Fatigue, Grain Boundary Diffusion

References

[1] D. Hull and D. E. Rimmer: Phil. Mag. Vol. 4 (1959) p.673.

[2] Y. Xu and J.L. Bassani: Mater. Sci. Engng. Vol. A260 (1999) p.48.

[3] J. A. Pfaendtner and C. J. McMahon, Jr.: Acta Mater. Vol. 49 (2001) p.3369.

[4] D. Bika, J. A. Pfaendtner, M. Menyhard, and C. J. McMahon, Jr.: Acta Metall. et Mater. Vol. 43 (1995) p. (1909).

[5] E. V. Barrera, M. Menyhard, D. Bika, B. Rothman, and C. J. McMahon, Jr.: Scripta Metall. Vol. 27 (1992) p.205.

[6] U. Krupp: Int. Mater. Rev., Vol. 50 (2005) p.83.

[7] W.M. Kane, U. Krupp, T. Jacobs, and C.J. McMahon Jr.: Mater. Sci. Engng. Vol. 402 (2005) p.42.

[8] U. Krupp, Ph. E. -G. Wagenhuber, W. M. Kane, and C.J. McMahon Jr.: Mater. Sci. Techn. Vol. 21 (2005) p.1247.

[9] U. Krupp, C.J. McMahon Jr.: J. Alloys Comp. Vol. 378 (2004) p.79.

[10] C.F. Miller, G.W. Simmons and R.P. Wei: Scripta Mater. Vol. 44 (2001) p.2405.

[11] R. Molins, G. Hochstetter, J.C. Chassaigne, and E. Andrieu: Acta Mater. Vol. 45 (1997) p.663.

[12] Y. Mishin and C. Herzig: Mater Sci. Engng. A, Vol. 260 (1999) p.55.

[13] U. Krupp: Fatigue Crack Propagation in Metals and Alloys (Wiley VCH 2006, in press).

[14] U. Krupp, W. M. Kane, X-Y Liu, O. Dueber, C. Laird, and C. J. McMahon, Jr.: Mater Sci. Engng. A, Vol. 349 (2003) p.213.

[15] R. C. Muthiah, J. A. Pfaendtner, S. Ishikawa, and C. J. McMahon, Jr.: Acta Mater. Vol. 47 (1999) p.2797.