Abstract
An observation of the dislocation mechanisms operating below a naturally initiated hot-salt stress corrosion crack is presented, suggesting how hydrogen may contribute to embrittlement. The observations are consistent with the hydrogen-enhanced localized plasticity mechanism. Dislocation activity has been investigated through post-mortem examination of thin foils prepared by focused ion beam milling, lifted directly from the fracture surface. The results are in agreement with the existing studies, suggesting that hydrogen enhances dislocation motion. It is found that the presence of hydrogen in (solid) solution results in dislocation motion on slip systems that would not normally be expected to be active. A rationale is presented regarding the interplay of dislocation density and the hydrogen diffusion length.
| Original language | English |
|---|---|
| Pages (from-to) | 282-292 |
| Number of pages | 11 |
| Journal | Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science |
| Volume | 47 |
| Issue number | 1 |
| Early online date | 19 Oct 2015 |
| DOIs | |
| Publication status | Published - 1 Jan 2016 |
Funding
The authors wish to acknowledge support from Rolls-Royce plc throughout this work. We would also like to thank the numerous people involved, who are based at Rolls-Royce Derby, Bristol, and Dahlewitz. The authors would also like to acknowledge the very useful discussions with Professor Ian Jones. Finally, we are grateful for the funding from the EPSRC; Grants EP/H004882/1 and EP/K034332/1, as well as a DTA CASE conversion EP/J500239/1 for T.P.C.
Keywords
- fatigue crack
- stress corrosion cracking
- edge dislocation
- hydrogen diffusion
- critical resolve shear stress