Effects of hydrogen on ductile fracture of a spheroidized low alloy steel

The effects of low activity hydrogen charging on the mechanical properties were studied in a low alloy spheroidized steel. Hydrogen charging was done either from the gas phase or from electrolytic solution. Monotonic tensile tests and microstructural observations both indicated that hydrogen-dislocation interactions are important. The results showed that hydrogen is accumulated during plastic deformation by dislocation sweep-in. Further, the presence of hydrogen was observed to lead to enhanced plasticity and damage localization. It is inferred that depending on the hydrogen concentration locally accumulated hydrogen can assist both void nucleation at internal interfaces by lowering of the cohesive forces and void growth by strain localization.