Studies of SCC and Hydrogen Embrittlement of High Strength Alloys Using Fracture Mechanics Methods


Article Preview

Fracture mechanics based test and evaluation techniques are used to gain insight into the phenomenon of stress corrosion cracking (SCC) and to develop guidance for avoiding or controlling SCC. Complementary to well known constant load and constant deflection test methods experiments that are based on rising load or rising displacement situations and are specified in the new ISO standard 7539 – Part 9 may be applied to achieve these goals. These are particularly suitable to study cases of SCC and hydrogen embrittlement of high strength steels, aluminium and titanium alloys and to characterise the susceptibility of these materials to environmentally assisted cracking. In addition, the data generated in such R-curve tests can be used to model the degradation of the material caused by the uptake of atomic hydrogen from the environment. This is shown for the case of a high strength structural steel (FeE 690T) where in fracture mechanics SCC tests on pre-cracked C(T) specimens a correlation between the rate of change in plastic deformation and the crack extension rate due to hydrogen embrittlement was established. The influence of plastic strain on the hydrogen diffusion was additionally studied by electrochemical permeation experiments. By modelling this diffusion based on the assumption that trapping of the hydrogen atoms takes place at trap sites which are generated by the plastic deformation, a good agreement was achieved between experimentally obtained data and model predictions.



Edited by:

Jaroslav Pokluda




W. Dietzel et al., "Studies of SCC and Hydrogen Embrittlement of High Strength Alloys Using Fracture Mechanics Methods", Materials Science Forum, Vol. 482, pp. 11-16, 2005

Online since:

April 2005




[1] B.F. Brown: Philos. Trans. R. Soc. Vol. A 282 (1976), p.235.

[2] H.H. Johnson and A.M. Willner: Appl. Mat. Res. Vol. 4 (1965), p.34.

[3] M.O. Speidel: The Theory of Stress Corrosion Cracking (NATO, Brussels 1971), p.289.

[4] D. Hellmann and K. -H. Schwalbe: The Crack Tip Opening Displacement in Elastic-Plastic Fracture Mechanics (Springer Verlag, Berlin-Heidelberg-New York 1986), p.115.


[5] W. Dietzel and K. -H. Schwalbe: Hydrogen Effects on Material Behavior (TMS, Warrendale, PA, 1990), p.975.

[6] W. Dietzel: Report GKSS 91/E/27 (GKSS, Geesthacht 1991).

[7] W. Dietzel, M. Pfuff, and G.G. Juilfs: Proceedings of EDEM'2003 (Bordeaux, France 2003).

[8] M.A.V. Devanathan and Z. Stachursky: Proc. Roy. Soc., Vol. A 270 (1962), p.90.

[9] G.G. Juilfs: Report GKSS 2001/16 (GKSS, Geesthacht 2001).

[10] R.A. Oriani: Acta Metall. Vol. 18 (1970) p.147.

[11] H.H. Johnson and R.W. Lin: Hydrogen Effects in Metal (Metallurgical Society of AIME, New York, 1981) p.3.

[12] A.H.M. Krom, R.W.J. Koers, and A. Bakker: J. Mech. Phys. Solids Vol. 47 (1999) p.971.

[13] R.B. Hutchings and A. Turnbull: Corrosion Science Vol. 33, 5 (1992) p.713.

[14] M. Kurkela, G.S. Frankel, R.M. Latanision, S. Suresh, and R.O. Ritchie: Scripta Met. Vol 16 (1982) p.455.