Hydrogen effect on cyclic plasticity and crack growth in coarse-grained iron

The effects of hydrogen with a concentration of ∼0.1 mass ppm on cyclic plasticity and crack growth were investigated on a Fe–0.01 mass% C alloy. In polycrystalline specimens, the grains covered with multiple gliding were decreased but those including discrete slip bands were increased in the presence of hydrogen. The hydrogen effect on cyclic plasticity of the coarse-grained specimens is characterized by the increased spacing and the decreased height of slip bands. Crystallographic crack growth was retained in the hydrogen-charged specimen unlike the uncharged specimen. This suggests that dissolved hydrogen restricts the number of the activated slip systems at the crack tip.