A comparison was made between hydrogen-induced corrosion fatigue crack growth (FCG) rates and critical distances ahead of the growing crack. This comparison was made by using results obtained from previous experiments on the corrosion FCG behavior of high-strength steels, titanium alloys, and a magnesium alloy. The critical distances included the distance to the location of maximum triaxial stress ahead of the crack, the sizes of cyclic and monotonic plastic zones, the depths of hydrogen penetration due to lattice diffilsion and dislocation sweeping. Hydrogen-induced corrosion FCG rates were presented as increments of crack growth per cycle. Critical distances ahead of the crack were calculated from the equations of continuum mechanics of solids. Some of possible cases that were discovered from the comparison did not
agree with well-known and conventional theoretical views on
hydrogen-induced cracking and hydrogen-induced FCG mechanisms.
Keywords: cathodic polarization, corrosion fatigue, crack growth, fracture process zone, high-strength steels, hydrogen- induced cracking, magnesium alloy, stress intensity, titanium alloys