Abstract
The anodic dissolution and hydrogen absorption for A537 steel in 3.5% NaCl solution, as studied by speckle interferometry, occur simultaneously at the fatigue crack tip. However, the degree of anodic dissolution and hydrogen embrittlement vary with applied potential. The anodic dissolution of the steel increases the plastic zone size at the crack tip, while the absorption of hydrogen into steel decreases the plastic zone size at the crack tip. In fact, the size of the plastic zone at the crack tip is determined by the competition of the above two processes, i.e., the size of the plastic zone at the crack tip will decrease if hydrogen absorption plays a dominant role, and will increase if anodic dissolution plays a dominant role.
