EFFECT OF HYDROGEN ON FATIGUE-CRACK GROWTH OF A FERRITIC-PEARLITIC LOW CARBON STEEL

摘要

The effect of external high-pressure H_2 gas on fatigue-crack growth behavior has been examined using a ferritic-pearlitic low carbon steel. The presence of hydrogen accelerates the crack growth rate by ≈13 times compared to the uncharged state and shifts the fracture surface morphology from ductile striations to a mixture of "flat" and "quasi-cleavage" features. The common feature found in the microstructure immediately beneath the hydrogen-induced fracture surface is enhanced plasticity in terms of refined dislocation cell structures and dense dislocation bands.