Effect of intergranular surface attack on the fatigue and corrosion properties of AM-355 CRT material
- Army Aviation Troop Command, St. Louis, MO (United States)
- Westar Corp., St. Louis, MO (United States)
- Army Research Lab., Aberdeen Proving Ground, MD (United States)
A dynamic part, consisting of a stack of laminates, failed in the field after an unexpectedly short life. Failure analysis showed that a multitude of fatigue cracks originated from a combination of corrosion and fretting. Recent changes in the production process of the laminates resulted in the presence of an intergranular (IG) morphology on the surface. Due to the criticality of this part`s application, a better understanding of the influence of varying degrees of IG attack on fatigue properties was pursued. Coupon specimens were machined from actual components with different surface IG conditions and were subjected to fatigue testing. Results showed a direct relationship between the number of cycles to failure and the severity of surface IG attack. Potentiodynamic polarization measurements indicated that a sample with IG attack had a lower breakdown potential and an unstable passivation behavior as compared to that without an IG attack. The detrimental effects of surface IG attack on the crack initiation process, endurance limit and corrosion resistance is discussed in terms of the stress concentration and breakdown of the passivation layer.
- OSTI ID:
- 335423
- Report Number(s):
- CONF-9705309-; ISBN 0-8031-2485-6; TRN: IM9918%%208
- Resource Relation:
- Conference: Symposium on effects of product quality and design on structural integrity, St. Louis, MO (United States), 5 May 1997; Other Information: PBD: 1998; Related Information: Is Part Of Effects of product quality and design criteria on structural integrity; Rice, R.C.; Tritsch, D.E. [eds.]; PB: 202 p.; ASTM special technical publication, 1337
- Country of Publication:
- United States
- Language:
- English
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