Journal of Materials Science

, Volume 14, Issue 10, pp 2459–2470 | Cite as

Electron metallography of the aluminium-water vapour reaction and its relevance to stress-corrosion susceptibility

  • G. M. Scamans
  • A. S. Rehal


The reaction of filmed surfaces of aluminium and certain aluminium alloys with water vapour saturated air at 70° C has been morphologically studied at high resolution using a JEOL 100C Temscan. Electron-transparent specimens, reacted for up to 24 h, have been examined using a combination of SE (secondary electron) and STE (scanning transmission electron) imaging modes to examine both the surface attack detail and the underlying microstructure of precisely located areas. Reaction on filmed surfaces is initiated by a hydrogen-induced blistering of the amorphous oxide film, the fracture of which results in the development of pseudoboehmite and bayerite on the bared metal surface. Alloying additions of magnesium localize the breakdown reaction at grain boundary-surface intersections, although this effect can be controlled by raising the solution heat treatment temperature to 550° C. The localization of the reaction results in hydrogen penetration of grain boundaries in magnesium-containing alloys, and this promotes a loss of grain-boundary strength and may lead to alloy failure by stress-corrosion cracking.


Boehmite Solution Heat Treatment Bayerite Hydroxide Film A1Mg Alloy 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    G. M. Scamans, R. Alani andP. R. Swann,Corros. Sci. 16 (1976) 443.CrossRefGoogle Scholar
  2. 2.
    M. O. Spiedel, “The theory of stress corrosion cracking in alloys”, edited by J. C. Scully (NATO, Brussels, 1971) p. 289.Google Scholar
  3. 3.
    R. S. Alwitt, “Oxide and oxide films”, Vol. 4, edited by J. W. Diggle (Marcel Dekker, New York, 1976) p. 169.Google Scholar
  4. 4.
    R. K. Hart,Trans. Faraday Soc. 53 (1957) 1020.CrossRefGoogle Scholar
  5. 5.
    G. C. Bye andJ. G. Robinson,Chem. & Ind. (1963) 612.Google Scholar
  6. 6.
    W. J. Bernard andJ. J. Randall Jr,J. Electrochem. Soc. 107 (1960) 483.CrossRefGoogle Scholar
  7. 7.
    R. S. Alwitt andL. C. Archibald,Corros. Sci. 13 (1973) 687.CrossRefGoogle Scholar
  8. 8.
    W. Vedder andD. A. Vermilyea,Trans. Faraday Soc. 65 (1969) 561.CrossRefGoogle Scholar
  9. 9.
    W. E. Neale andA. S. Rehal, Symposium on contamination control, Washington, September (1978).Google Scholar
  10. 10.
    G. M. Scamans,J. Mater. Sci. 13 (1978) 27.CrossRefGoogle Scholar
  11. 11.
    M. S. Hunter andP. Fowle,J. Electrochem. Soc. 103 (1956) 482.CrossRefGoogle Scholar
  12. 12.
    F. P. Fehlner andN. F. Mott,J. Oxid. Metals 2 (1970) 59.CrossRefGoogle Scholar
  13. 13.
    M. J. Pryor,ibid. 3 (1971) 271.CrossRefGoogle Scholar
  14. 14.
    Idem, ibid. 3 (1971) 523.CrossRefGoogle Scholar
  15. 15.
    A. F. Beck, M. A. Heine, E. J. Caule andM. J. Pryor,Corros. Sci. 7 (1967) 1.CrossRefGoogle Scholar
  16. 16.
    H. M. Flower andP. R. Swann,ibid. 17 (1977) 305.CrossRefGoogle Scholar
  17. 17.
    C. B. Bargeron andR. B. Givens,J. Electrochem. Soc. 124 (1977) 1845.CrossRefGoogle Scholar
  18. 18.
    H. M. Flower,Rad. Effects 33 (1977) 173.CrossRefGoogle Scholar
  19. 19.
    J. M. Chen, T. S. Sun, R. K. Viswanadham andJ. A. S. Green,Met. Trans. A 8A (1977) 1935.CrossRefGoogle Scholar
  20. 20.
    I. T. Taylor andR. L. Edgar,Met. Trans. 2 (1970) 833.CrossRefGoogle Scholar
  21. 21.
    G. M. Scamans andC. D. S. Tuck, Environmentsensitive fracture of engineering materials, TMS-AIME, Chicago (1977).Google Scholar

Copyright information

© Chapman and Hall Ltd. 1979

Authors and Affiliations

  • G. M. Scamans
    • 1
  • A. S. Rehal
    • 1
  1. 1.Alcan Laboratories LimitedBanburyUK

Personalised recommendations