FRACTURE TOUGHNESS, FATIGUE-CRACK PROPAGATION AND CORROSION CHARACTERISTICS OF ALUMINUM ALLOY PLATES FOR WING SKINS.
Abstract
The fracture toughness, fatigue properties and corrosion resistance of 2020-T651, 2024-T851, 2219-T851 and 7001-T75 are being determined. Fracture-toughness tests of 1-in. specimens of the 2020-T651, 2219-T851 and 7001-T75 were completed during the past quarter. The fracture toughness of 2020-T651 is lowest; those of 7001-T75 and 2024-T851 are higher but still about 20 per cent below that of 7075-T651 (from AF33(657)-11155). The fracture toughness of 2219-T851 is exceptionally high, equalling or exceeding that of 7075-T7351. Fatigue tests of center-notched specimens of 2020-T651 and 2219-T851 are complete. Cracks initiate in about the same number of cycles for 2219-T851 as for 2024-T851, and slightly sooner than in 2020-T651 and 7075-T651. Cracks propagate more slowly in 2219-T851 and 2020T651 than in some of the other alloys, but 2020-T651 fails at shorter crack lengths. Corrosion tests show that 2020-T651, 2024-T851 and 2219-T851 are highly resistant to exfoliation attack and to stress-corrosion cracking in any direction at stresses up to 75 per cent of the yield strength, similar to the case for 7075-T7351. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 15, 1965
- Accession Number
- AD0625454
Entities
People
- B. W. Lifka
- G. E. Nordmark
- J. G. Kaufman