Life prediction under stress corrosion conditions below K/sub ISCC/
Under stress corrosion conditions, the major portion of the useful life of a structure, originally free of defects, is spent during incubation and growth of microcracks. On the other hand, microcrack initiation is one of the least-well-understood phenomena and a prediction of the remaining life of a component in service is very difficult. Therefore, a physical model was developed which, at the present time, is specific to stress-corrosion cracking (S.C.C.) of Cu-30Zn brass in a nontarnishing ammoniacal solution. The predictions of the model in terms of time to initiation were tested using experimental data of the effects of applied stress on crack initiation. Metallographic observations and scanning electron microscopy provided information on the transition from corrosion pitting to microcrack initiation. This transition occurs at a critical pit size of about ..mu..m, which will increase with decreasing stress. implications of this research on nondestructive evaluation of S.C.C. in the microcrack-initiation regime are briefly discussed.
- Research Organization:
- Ames Lab., IA (USA)
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 5617231
- Report Number(s):
- IS-M-455; CONF-830811-12; ON: DE83018074
- Country of Publication:
- United States
- Language:
- English
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