MODELLING THE SLOW CRACK GROWTH DUE TO INTERNAL HYDROGEN IN METALS

摘要

Hydrogen-induced slow crack growth generally exhibits three distinct stages of crack growth kinetics, and stages I and II are hydrogen diffusion-controlled. A model describing the crack growth kinetics of stages I and II due to internal hydrogen is proposed, based on the linear-elastic fracture mechanics, stress-induced hydrogen diffusion theory and hydrogen-enhanced decohesion mechanism for hydrogen-induced cracking. The model predicts the crack growth rate daldt of both stages I and II as a function of the stress intensity factor K_1 and initial hydrogen concentration level. Some experimental data reported in literature are used to validate the model and a good agreement is obtained.