THE EFFECT OF HISTORY ON HYDROGEN-ASSISTED CRACKING - 2 - A REVISION OF K-DOMINANCE

In Part 1 of this work it was shown that, because of the coupling of t he processes of crack growth and hydrogen accumulation in rupture site s, the crack growth kinetics curve nu = nu(K) in hydrogen assisted cra cking (HAC) does not possess intrinsic uniqueness as a material's char acteristic curve. This paper presents an analytical treatment of the p henomenon and a special regime of steady-state crack growth is seen to exist for which hydrogen assisted cracking turns out to be a K-domina ted process. The corresponding plot of the steady-state nu against K a cquires the uniqueness of a material's characteristic curve which may be used in engineering to provide more conservative evaluation of mate rial resistance and structural integrity in HAC conditions. Inherent u ncertainties in the customary fracture mechanics approach to HAC are a nalysed in an attempt to guide the way towards its further refinement.