Enhanced hydrogen concentrations ahead of rounded notches and cracks—competition between plastic strain and hydrostatic stress
✍ Scribed by J Lufrano; P Sofronis
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 311 KB
- Volume
- 46
- Category
- Article
- ISSN
- 1359-6454
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✦ Synopsis
AbstractÐThe ®nite element method was used to solve the coupled elastic±plastic boundary value problem and transient hydrogen diusion initial boundary value problem. Solutions were obtained at room temperature and under plane strain deformation in the neighborhood of a blunting crack tip under small scale yielding conditions and in the neighborhood of a rounded notch in a four-point bend specimen. The hydrogen population pro®les in both normal interstitial lattice sites (NILS) and trapping sites were calculated and conditions for the predominance of the total amount of hydrogen by either of the populations were studied. A discussion of the ®nite element results in conjunction with dierent mechanisms of hydrogen embrittlement is presented. If a critical amount of hydrogen is required for hydrogen induced crack initiation, the present results predict locations of crack initiation sites at steel bend specimens which are in agreement with experimental observations on the occurrence of the ®rst microcracking event. # 1998 Acta Metallurgica Inc.