Abstract
The mechanisms of grain refinement have been examined for magnetically stirred gas tungsten arc (GTA) welds completely penetrating thin sheets of several aluminum alloys. Grain refinement in unstirred welds may be brought about by adding sufficient titanium to produce heterogeneous nucleation by Ti-rich particles. In some alloys magnetic stirring is shown to extend the range of welding conditions which produce a partially equiaxed structure, and to widen the equiaxed fraction of partially equiaxed welds. This is attributed to magnetic stirring lowering the temperature gradient, allowing nucleation and growth of Al-rich grains further ahead of the columnar interface growing in from the fusion boundaries. In alloys with low Ti levels, magnetic stirring may cause refinement by sweeping grains from the partially molten zone ahead of the advancing solidification interface. This mechanism requires that the partially molten zone be sufficiently wide, and that the grain size in this zone remain small.
Similar content being viewed by others
Reference
Y. Arata, F. Matsuda, and A. Matsui:Trans. Jpn Weld. Res. Inst., 1974, vol. 3, pp. 89–97.
T. Ganaha and H. W. Kerr:Metals Technology, 1978, vol. 5, pp. 62–69.
T. Ganaha, B. P. Pearce, and H. W. Kerr:Metall. Trans. A, 1980, vol. 11A, pp. 1351–59.
A. Cibula:J. Inst. Metals, 1951-52, vol. 80, pp. 1–16.
A. Cibula:J. Inst. Metals, 1949, vol. 76, pp. 321–60.
J. A. Marcantonio and L. F. Mondolfo:J. Inst. Metals, 1970, vol. 98, pp. 23–27.
G. W. Delamore and R. W. Smith:Metall. Trans., 1971, vol. 2, pp. 1733–38.
L. Backerud:Jernkontorets. Ann., 1971, vol. 155, pp. 422–24.
J. Cissé, H. W. Kerr, and G. F. Boiling:Metall. Trans., 1974, vol. 5, pp. 633–41.
D. H. St. John and L. M. Hogan:J. Aust. Inst. Metals, 1977, vol. 22, pp. 160–66.
A. J. Cornish:Metal Sci., 1975, vol. 9, pp. 477–84.
L. Arnberg, L. Backerud, and H. Klang: inSolidification Technology in the Foundry and Casthouse, Metals Society, London, 1980.
F. Matsuda, H. Nakagawa, K. Nakata, and R. Ayani:Trans. Jpn Weld. Res. Inst., 1978, vol. 7, pp. 111–27.
F. Matsuda, K. Nakata, Y. Miyanaga, T. Kayano, and K. Tsukamoto:Trans. Jpn Weld. Res. Inst., 1978, vol. 7, pp. 181–93.
V. P. Chernysh and V. A. Pakhareako:Auto. Weld., 1979, no. 5, pp. 12–14.
V. S. Gvozdetskii and V. S. Mechev:Auto. Weld., 1963, no. 12, pp. 1–5.
W. H. S. Lawson and H. W. Kerr:Weld. Res. Intl., 1976, vol. 6, no. 6, pp. 73–77 and 6, no. 6, pp. 1-17.
T. Ganaha and H. W. Kerr:Metall. Trans. B, 1978, vol. 9B, pp. 313–16.
J. P. Sadocha and H. W. Kerr:Met. Sci. J., 1973, vol. 7, pp. 138–46.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Pearce, B.P., Kerr, H.W. Grain refinement in magnetically stirred GTA welds of aluminum alloys. Metall Trans B 12, 479–486 (1981). https://doi.org/10.1007/BF02654317
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02654317