The interaction of hydrogen with dislocation in iron

Abstract

The interaction of hydrogen with dislocation was studied by the thermal analysis technique using a gas chromatograph as hydrogen detector. The amount of hydrogen trapped at dislocation was measured and its relation with dislocation arrangements was studied. The effect of hydrogen on dislocation mobility was also studied by monitoring the change of the dislocation arrangement under the different heat treating atmospheres. The amount of hydrogen trapped at dislocation as observed in the thermal analysis was increased when the densely tangled dislocations are loosened by the repeated thermal analysis. This shows that hydrogen is trapped at the stress field of dislocation mot at the core. The position of evolution rate peak which related to the activation energy of the hydrogen release from dislocation did not depend on the dislocation arrangements. The dislocation rearrangement proceeds more rapidly when specimen is heat treated under the hydrogen atmosphere than under vacuum, and the dislocation mobility is increased by hydrogen.