Abstract
The effect of quench rate on alloys with a bcomposition of 6.75 pct Zn, 2.5 pct Mg, 1.2 pct Cu and various levels and combinations of the minor addition elements (MAE’s) Cr, Mn, and Zr is reported. The level of chromium and to a lesser extent the level of zirconium determine quench sensitivity. Slow quenching of chromium- or zirconium-bearing alloys led to the nucleation of (MgZn) plates or laths at MAE-bearing particles which had certain orientation relationships with the matrix. The density of the hardening precipitation (100 to 200Å in diam) was found to be high in slowly quenched, sensitive alloys. Even when the yield strength had fallen to 50 pct of that of the fast-quenched material, a large fraction of the fine precipitate was still formed. A fracture mechanism is proposed to account for the magnitude of quench sensitivity in such materials. An embrittlement, at low quench rates, was found in alloys containing manganese or very low levels of MAE. This embrittlement was thought to be due to precipitation in the grain boundaries, and not to the width of the precipitate-free zone.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
W. L. Fink and L. A. Willey :Quenching of 75S Aluminum Alloy, AIME Tech. Pub. no. 2225, 1947. Metals Technol., Aug. 1947, vol. 14, no. 5.
J. E. Vruggink: “Quenching Rate Effects on Mechanical Properties of Heat-treatable Aluminum Alloys”, TMS Paper Selection No. A68-50. The Met. Soc. of AIME New York, 1968.
O. R. Singleton:J. Metals, 1968, vol. 21, pp. 60–67.
H. Y. Hunsicker:The Metallurgy of Heat Treatment, horn Aluminum, Vol. I, K. R. VanHorn, ed., ASM Metals Park, Ohio, 1967.
Y. Baba:Trans. Jap. Inst. Metals, 1968, vol. 9 (Suppl.), pp. 356–60.
A. J. Bryant:Z. Metallic., 1967, vol. 58, pp. 684–91.
H. A. Holl:J. Inst. Metals, 1969, vol. 97, pp. 200–05.
R. Chadwick, N. D. Muir, and H. B. Grainger:J Inst. Metals, 1956-57, vol. 85, pp. 161–70.
D. Adenis, J. P. Moulin, and A. Guilhaudis:Mem. Sci. Rev. Met., 1969, vol. 66, pp. 135–49.
L. A. Willey:Phase Diagrams horn Aluminum, Vol. I, K. R. VanHorn, ed., ASM, Metals Park, Ohio, 1967.
B. Thundal and R. Sundberg:J. Inst. Metals, 1969, vol. 97, p. 160.
P. C. Varley, M. K. B. Day, and A. Sendorek:J. Inst. Metals, 1957-58, vol. 86, pp. 337–51.
D. O. Sprowls and R. H. Brown: inProc. Intern. Conf. on Fundamental Aspects of Stress Corrosion Cracking, pp. 466-506, Columbus, Ohio, Sept. 1967.
P. A. Thackery:J. Inst. Metals, 1968, vol. 96, pp. 228–35.
W. F. Smith and N. J. Grant:Met. Trans., 1970, vol. 1, pp. 1735–40.
E. A. Starke:J. Metals, 1970, vol. 22, pp. 54–63.
A. J. Sedricks, P. W. Slattery, and E. N. Pugh:ASM Trans. Quart., 1969, vol. 62, pp. 815–18.
G. Thomas and J. Nutting:J. Inst. Metals, 1959-60, vol. 88, pp. 81–90.
N. Ryum, B. Haegland, and T. Lindtveit:Z. Metallk., 1967, vol. 58, pp. 28–31.
N. Ryum:Acta Met., 1968, vol. 16, pp. 327–32.
H. A. Holl:Corrosion, 1967, vol. 23, pp. 173–80.
P. N. T. Unwin and G. C. Smith:J. Inst. Metals, 1969, vol. 97, pp. 299–310.
A. Giarda and E. Di Russo:Alluminio, 1969, vol. 38, pp. 615–19.
P. N. T. Unwin and R. B. Nicholson:Acta Met., 1969, vol. 17, pp. 1379–93.
A. J. Cornish and M. K. B. Day:J. Inst. Metals, 1969, vol. 97, pp. 44–52.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Thompson, D.S., Subramanya, B.S. & Levy, S.A. Quench rate effects in Al-Zn-Mg-Cu alloys. Metall Trans 2, 1149–1160 (1971). https://doi.org/10.1007/BF02664247
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02664247