Stress corrosion resistance of damage tolerant aluminium-lithium sheet materials

Stress corrosion resistance of damage tolerant aluminium-lithium sheet materials

Kolkman, H.J.
Schra, L.

National Aerospace Laboratory NLR

1991-09-01

The SCC resistances of three damage tolerant aluminium sheet materials were determined by means of the ASCOR (Automated Stress Corrosion Ring) test. The conventional damage tolerant sheet material 2024-T3 was used as reference. The sec resistance of 8090-T81 turned out to be only slightly lower than the sec resistance of 2024-T3. In contrast, 2091-T8X exhibited a much lower SCC resistance. However, the so-called CPHK treatment brought the SCC resistance of 2091-T8X to the level of 2024-T3 and 8090-T81. The favourable effect of the CPHK treatment is -at least partly- explained by the grain structure: The pancake grain structure of 2091-T8X-ePHK (as compared with the equiaxed grain structure of 2091-T8X) hinders SC crack growth. Other microstructural differences between 2091-T8X and 2091-T8X-CPHK were not found. The subject of grain boundary segregation was not touched upon, however, and deserves attention.

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Nationaal Lucht- en Ruimtevaartlaboratorium

Campus only

NLR Technical Publication TP 91399 L

Aerospace Engineering Reports

report

(c)1991 National Aerospace Laboratory NLR