Abstract
To clarify the correlation between the hydrogen embrittlement and the hydride (β-phase) formation in transition metals, Ni-Cu binary alloys have been investigated by means of electrolytic hydrogen charging and X-ray diffraction methods. The hydride formation was controlled by varying three factors, i.e., copper content, charging current-density and temperature. In any case of these three factors, it was found that independent of hydrogen content the hydrogen embrittlement occurred always only when the hydride was formed. It was concluded that the hydrogen embrittlement can be ascribed to the discontinuous expansion which accompanies the α-β transformation (hydride formation) caused by the change in hydrogen concentration.
