Abstract
The precipitation behaviors and aging reactions of the pseudobinary Al-Cu-Mg alloy and the commercial 2024 alloy under unstretched and stretched conditions have been investigated in this study by means of conductivity and hardness measurements, differential scanning calorimetry, and transmission electron microscopy (TEM). The morphologies and growth modes of various defects and transition phases as well as the interaction among them were widely discussed. In particular, an electron diffraction ring pattern was found to correspond to the axial growth of the GPB2 zone. This suggested that the atom groups constructing this cylindrical zone are statistically, uniformly arranged in the adjacent {100}A1 planes and the GPB2 zone is only a partially ordered version of the GPB zone in <001>Al, directions. Moreover, few GPB2 zones can survive long time overaging due to the Gibbs-Thomson effect. As for the S' precipitates, they preferentially nucleate on dislocations. During subsequent growth, they can further coalesce into two morphologies (corrugated sheets and wide plates) for the unstretched specimens. However, for the stretched specimens, this coalescing process does not occur until a long time of overaging due to more introduced dislocations. Therefore, the rate of Ostward ripening decreases and the peak hardness becomes flattened. Finally, based on the present analyses, the aging sequence of the two alloys studied could be revised with respect to previous investigations and their isothermal aging reactions can be subdivided into five main stages. These stages correspond to (1) GPB zone precipitation, (2) fast in situ precipitation of GPB2 zones from GPB zones and their subsequent growth, (3) fast nucleation and accelerating growth of the S' phase, (4) decelerating growth of the S' phase, and (5) Ostward ripening of the S' and S phases, respectively.
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T.H. Sanders, Jr. and E.A. Starke, Jr.:Metall. Trans. A, 1976, vol. 7A, pp. 1407–18.
G.M. Ludtka and D.E. Laughlin:Metall. Trans. A, 1981, vol. 12A, pp. 2083–91.
G.M. Ludtka and D.E. Laughlin:Metall. Trans. A, 1982, vol. 13A, pp. 411–25.
J.T. Vietz and I.J. Polmear:J. Inst. Met., 1966, vol. 94, pp. 410–19.
R.N. Wilson, D.M. Moore, and P.J.E. Forsyth:J. Inst. Met., 1967, vol. 95, pp. 177–83.
R.N. Wilson:J. Inst. Met., 1969, vol. 97, pp. 80–86.
N. Sen and D.R.F. West:J. Inst. Met., 1969, vol. 97, pp. 87–92.
F.S. Lin, S.B. Chakrabortty, and E.A. Starke, Jr.:Metall. Trans. A, 1982, vol. 13A, pp. 401–10.
F.G. Ostermann and W.H. Reimann: ASTM STP 467, ASTM, Philadelphia, PA, 1970, pp. 169-87.
F. Ostermann:Metall. Trans., 1971, vol. 2, pp. 2897–2902.
M.C. Chaturvedi, D.W. Chung, and R.A. Doucette:Met. Sci., 1979, pp. 34-38.
R.N. Wilson and P.G. Partridge:Acta Metall., 1964, vol. 13, pp. 1321–27.
H.K. Hardy:J. Inst. Met., 1954-55, vol. 83, pp. 17–34.
J.M. Silcock: J. Inst. Met., 1960-61, vol. 89 pp. 203–10.
L.F. Mondolfo:Aluminum Alloys: Structure and Properties, Butterworth and Co., Boston, MA, 1976, pp. 497–505.
T.V. Shchegolayev and N.N. Buynov:Fiz. Met. Metalloved., 1967, vol. 23, pp. 1026–32.
R. Horiuchi and Y. Minonishi:J. Jpn. Inst. Met., 1970, vol. 39, pp. 936–43.
W.V. Youdelis and W. Fang:Science and Engineering of Light Metals, Japan Institute of Light Metals, Tokyo, 1991, pp. 917–22.
T. Croucher and D. Butler:Heat Treating of Light Metals, Japan Institute of Light Metals, Tokyo, 1983, pp. 18–19.
M. Rosen and E. Horowitz:Mater. Sci. Eng., 1982, vol. 53, pp. 191–98.
A.K. Jena, A.K. Gupta, and M.C. Chaturvedi:Acta Metall., 1989, vol. 37, pp. 885–95.
P.L. Rossiter and P. Wells:Phil. Mag., 1971, vol. 24, pp. 425–36.
Richard DeIasi and Philip N. Adler:Metall. Trans. A, 1977, vol. 8A, pp. 1177–83.
H.D. Chandler and J.V. Bee:Acta Metall., 1987, vol. 35, pp. 2503- 10.
W. Bonfield and P.K. Datta:J. Met. Sci., 1976, vol. 11, pp. 1661–66.
G. Pysz and I. Tietz:Neue Hüttz, 1968, vol. 13, pp. 432–34.
A. Saulnier and R. Syre:Rev. Met., 1952, vol. 49, p. 1.
Yu. A. Bagaryatsky:Dokl. Akad. Nauk SSSR, 1952, vol. 87, p. 397.
T.V. Shchegoleva and N.N. Buinov:Sov. Phys.-Crystallogr., 1968, vol. 12, pp. 552–55.
Yu.A. Bagaryatsky:Z. Tekhn. Fiz., 1948, vol. 18, p. 827.
Yu.A. Bagaryatsky:Z. Tekhn. Fiz., 1950, vol. 20, pp. 424–27.
Yu.A. Bagaryatsky:Dokl. Akad. Nauk, 1952, vol. 87, p. 559.
G.C. Weatherly: Ph.D. Thesis, University of Cambridge, Cambridge, United Kingdom, 1966.
V. Radmilovic, G. Thomas, G.J. Shiflet, and E.A. Starke, Jr.:Scripta Metall., 1989, vol. 23, pp. 1141–46.
A.K. Gupta, P. Gaunt, and M.C. Chaturvedi:Phil. Mag., 1987, vol. 55, 375–87.
D.A. Porter and K.E. Easterling:Phase Transformations in Metals and Alloys, 1st ed., Pergamon Press, Oxford, United Kingdom, 1981.
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Shih, HC., Ho, NJ. & Huang, J.C. Precipitation behaviors in Al-Cu-Mg and 2024 aluminum alloys. Metall Mater Trans A 27, 2479–2494 (1996). https://doi.org/10.1007/BF02652342
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DOI: https://doi.org/10.1007/BF02652342