It was found that crack opening stress intensities are not constant after holding for various times in the unloaded state for iron and a sequence of Fe-Si binary alloys. The crack opening level decreased with time first because of asperity creep and substructure relaxation, and then increased again with time due to reverse plastic zone relaxation allowing a new set of asperities to come into contact. It is demonstrated that the crack closure phenomenon is not only a result of residual plasticity, oxidation and asperities, but also is due to asperity creep and reverse plastic zone relaxation at the crack tip for low strength materials.
|Original language||English (US)|
|Number of pages||11|
|Journal||Fatigue of Engineering Materials and Structures|
|State||Published - Jan 1 1985|