Microcrack initiation mechanism in hydrogen induced cracking in nickel

ABSTRACT

It is well known that cracks are observed on the surface without load when pure nickel is left in ambient air after hydrogen charge. It has been due to the decomposition of nickel hydride generated during hydrogen charging. In the present work, microcracks were investigated at the surface and inside the specimen with suppressing the decomposition of nickel hydride in polycrystalline pure nickel. As a result, microcracks initiate in the nickel matrix near the hydride inside the specimen before hydride decomposition. The microcracks grow toward the specimen’s surface as hydride decomposition.

KEYWORDS:

• Nickel hydride
• hydrogen embrittlement
• microcrack initiation

Disclosure statement

No potential conflict of interest was reported by the author(s).