This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Metallurgical Examination of a Failed Blade Lag Shock Absorber from an Army Cargo Helicopter
Technical Paper
2000-01-2101
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
A metallurgical examination was performed on a failed blade lag shock absorber from the aft red rotor blade of an Army cargo helicopter. The U.S. Army Research Laboratory (ARL) and the primary contractor performed a visual examination of the failed part, fluorescent penetrate inspection, fractographic evaluation, metallography, hardness testing, conductivity testing and chemical analysis. It was concluded that the part failed in fatigue from an area exhibiting intergranular attack. The corrosive attack was most likely caused by the processing fluids used during the rework process, as it was later determined that an unapproved aqueous alkaline immersion cleaner was being used. Failure to meet the required yield strength may have been an indication that the parts were not properly aged. An improper aging treatment could have facilitated the intergranular attack.
Recommended Content
Citation
Pepi, M., "Metallurgical Examination of a Failed Blade Lag Shock Absorber from an Army Cargo Helicopter," SAE Technical Paper 2000-01-2101, 2000, https://doi.org/10.4271/2000-01-2101.Also In
References
- Courtesy of Corpus Christi Army Depot, September, 1995
- Davis, J.R. Aluminum and Aluminum Alloys”, ASM Specialty Handbook 1994 591
- Kennedy, J.R. Acoustic Emission During Deformation of Heat Treated 7075 Aluminum;, Metal Science, 18 June 1984 286
- Personal conversation with William Alvarez, AMCOM 26 January 1998
- Kennedy, J.R. Northrop Report 14 October 1991
- Military Specification MIL-H-6088, Kennedy, J.R. Heat Treatment of Aluminum Alloys 1 April 1991 8 53
- Davis, J.R. Aluminum and Aluminum Alloys,” ASM Specialty Handbook 1994 315