Abstract
Two commercially-processed Al-6Zn-2Mg alloys, 7050 and a “low copper” 7050, were tested for susceptibility to embrittlement by precharged hydrogen and by simultaneous cathodic charging and straining (SET procedure). Specimens were heat treated to underaged, peak-strength aged, and overaged conditions. In 7050, the peak strength and overaged conditions were not embrittled by hydrogen, though underaged material showed marked embrittlement. All microstructures tested for the low-copper alloy were embrittled. The results agree with the microstructural rationale established through earlier work on 7075 and 2124 aluminum alloys, particularly with respect to the susceptibility of underaged material to hydrogen. As in earlier work, the extent of dislocation transport of hydrogen, and local hydrogen accumulation at grain boundaries, evidently controlled the extent and degree of brittle fracture. These three important alloys can now be ranked in the order 7050, 2124, 7075 of increasing relative susceptibility to theonset of stress corrosion cracking.
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References
R. J. Gest and A. R. Troiano:L’hydrogen dans les Metaux, Editions Science et Industrie, Paris, 1972, pp. 427–32.
R. J. Gest and A. R. Troiano:Corrosion, 1974, vol. 30, pp. 274–79.
J. Albrecht, B. J. McTiernan, I. M. Bernstein, and A. W. Thompson:Scripta Met., 1977, vol. 11, pp. 393–97.
J. Albrecht, A. W. Thompson, and I. M. Bernstein:Metall. Trans. A, 1979, vol. 10A, pp. 1759–65.
M. Taheri, J. Albrecht, I. M. Bernstein, and A. W. Thompson:Scripta Met., 1979, vol. 13, pp. 871–75.
J. Albrecht, I. M. Bernstein, and A. W. Thompson:Metall. Trans. A, 1982, vol. 13A, pp. 811–20.
G.M. Seamans, R. Alani, and P.R. Swann:Corros. Sci., 1976, vol. 16, pp. 443–59.
J.A. S. Green, H.W. Hayden, and W. G. Montague:Effect of Hydrogen on Behavior of Materials, A. W. Thompson and I. M. Bernstein, eds., TMS-AIME, New York, NY, 1976, pp. 200–15.
R. E. Swanson, A. W. Thompson, I. M. Bernstein, and J. L. Maloney:Hydrogen Effects in Metals, I. M. Bernstein and A. W. Thompson, eds., TMS-AIME, Warrendale, PA, 1981, pp. 459–66.
N.J.H. Holroyd and D. Hardie:Corros. Sci., 1981, vol. 21, pp. 129–44.
J. Busby, J. F. Cleave, and R. L. Cudd:J. Inst. Metals, 1971, vol. 99, pp. 41–49.
M. O. Speidel and M. V. Hyatt:Advances in Corrosion Science and Technology, Plenum, New York, NY, 1972, vol. 2, pp. 115–335.
M.O. Speidel:Metall. Trans. A, 1975, vol. 6A, pp. 631–51.
C.J. Peel and P. Poole:Mechanisms of Environment Sensitive Cracking of Materials, Metals Soc, London, 1977, pp. 147–56.
J.M. Truscott, V. E. Carter, and H.S. Campbell:J. Inst. Metals, 1971, vol. 99, pp. 57–66.
B. Sarkar, M. Marek, and E. A. Starke:Metall. Trans. A, 1981, vol. 12A, pp. 1939–43.
A. W. Thompson and I. M. Bernstein:Advances in Corrosion Science and Technology, M. G. Fontana and R. W. Staehle, eds., Plenum Pub. Co., New York, NY, 1980, vol. 7, pp. 53–175.
T. H. Sanders and E. A. Starke:Metall. Trans. A, 1976, vol. 7A, pp. 1407–18.
F. -S. Lin and E. A. Starke:Mat. Sci. Eng., 1979, vol. 39, pp. 27–41.
A.W. Thompson and I. M. Bernstein:Reviews on Coatings and Corrosion, 1975, vol. 2, pp. 2–44.
J.L. Nelson and E. N. Pugh:Metall. Trans. A, 1975, vol. 6A, pp. 1459–60.
L. Christodoulou and H.M. Flower:Acta Met., 1980, vol. 28, pp. 481–87.
D.A. Hardwick, M. Taheri, A.W. Thompson, and I.M. Bernstein:Metall. Trans. A, 1982, vol. 13A, pp. 235–39.
A. Sendorek and A.W. Pearson:J. Inst. Metals, 1971, vol. 99, pp. 33–40.
J.K. Tien, A.W. Thompson, I.M. Bernstein, and R.J. Richards:Metall. Trans. A, 1976, vol. 7A, pp. 821–29.
J. P. Hirth and H.H. Johnson:Atomistics of Fracture, R.M. Latanision and J.R. Pickens, eds., Plenum, New York, NY, 1983, pp. 771–85.
T. F. Klimowicz and R.M. Latanision:Metall. Trans. A, 1978, vol. 9A, pp. 597–99.
I. M. Bernstein and A. W. Thompson:Alloy and Microstructural Design, J.K. Tien and G.S. Ansell, eds., Academic Press, New York, NY, 1976, pp. 303–47.
J. C. Scully:Effect of Hydrogen on Behavior of Materials, A. W. Thompson and I.M. Bernstein, eds., TMS-AIME, New York, NY, 1976, pp. 129–47.
A.W. Thompson:Mater. Sci. Eng., 1980, vol. 43, pp. 41–46.
A.W. Thompson and J.A. Brooks:Acta Met., 1982, vol. 30, pp. 2197–2203.
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Formerly Postdoctoral Associate at Carnegie-Mellon University.
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Hardwick, D.A., Thompson, A.W. & Bernstein, I.M. The effect of copper content and microstructure on the hydrogen embrittlement of AI-6Zn-2Mg alloys. Metall Trans A 14, 2517–2526 (1983). https://doi.org/10.1007/BF02668893
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DOI: https://doi.org/10.1007/BF02668893