Hostname: page-component-7479d7b7d-t6hkb Total loading time: 0 Render date: 2024-07-13T22:01:55.129Z Has data issue: false hasContentIssue false
  • English
  • Français

Metastable solidification of NdFeB alloys by drop-tube processing

Published online by Cambridge University Press:  31 January 2011

Jianrong Gao ,
Th. Volkmann  and
D. M. Herlach
Jianrong Gao*
Affiliation:
Institute of Space Simulation, DLR, D-51170 Cologne, Germany Department of Applied Physics, Northwestern Polytechnical University, Xian 710072, China
Th. Volkmann
Affiliation:
Institute of Space Simulation, DLR, D-51170 Cologne, Germany Institute of Experimental Physics, Ruhr University of Bochum, D-44780 Bochum, Germany
D. M. Herlach
Affiliation:
Institute of Space Simulation, DLR, D-51170 Cologne, Germany
*
a)Author all correspondence to this author.
Get access

Abstract

Metastable solidification of small droplets of Nd11.8Fe82.3B5.9 and Nd14Fe79B7 alloys was performed in an 8-m drop tube filled with helium. The results showed that the solidification path of the droplets depends on the alloy composition and on the droplet size. For Nd11.8Fe82.3B5.9 alloy, larger droplets are solidified by primary iron formation and subsequent Nd2Fe14B crystallization from the residual liquid phase, whereas smaller ones tend to be frozen by metastable primary Nd2Fe17Bx growth (x = 0–1). A similar transition of the solidification path from primary iron formation to primary Nd2Fe17Bx formation occurred in Nd14Fe79B7 alloy with reducing droplet size. However, metastable primary growth of Nd2Fe14B was also observed within a wide droplet size range prior to the appearance of the metastable Nd2Fe17Bx phase. Nucleation and growth of different phases were considered to produce an explanation of the observed phase selection phenomena in these two alloys.

Type
Articles
Information
Journal of Materials Research , Volume 16 , Issue 9 , September 2001 , pp. 2562 - 2567
Copyright
Copyright © Materials Research Society 2001

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1Sagawa, M., Fujimura, S., Togawa, N., Yamamoto, H., and Matsuura, Y., J. Appl. Phys. 55, 2083 (1984).Google Scholar
2Croat, JJ., Herbst, J.F., Lee, R.W., and Pinkerton, F.E., J. Appl. Phys. 55, 2078 (1984).CrossRefGoogle Scholar
3Seeger, M. and Kronmüller, H., Z. Metallkd. 87, 923 (1996).Google Scholar
4Scott, D.W., Ma, B.M., Liang, Y.L., and Bounds, C.O., J. Appl. Phys. 79, 4830 (1986).CrossRefGoogle Scholar
5Gao, J. and Wei, B., J. Alloys Compd. 285, 229 (1999).CrossRefGoogle Scholar
6Umeda, T., Okane, T., and Kurz, W., Acta Metall. 44, 4209 (1996).Google Scholar
7Gao, J., TVolkmann, h., and Herlach, D.M., J. Alloys Compd. 308, 296 (2000).CrossRefGoogle Scholar
8Gillessen, F. and Herlach, D.M., Mater. Sci. Eng. 97, 353 (1988).CrossRefGoogle Scholar
9Herlach, D.M., Mater. Sci. Eng. R 12, 177 (1994).Google Scholar
10Christian, J.W., The Theory of Transformations in Metals and Al-loys, 2nd ed. (Pergamon, Oxford, U.K., 1975), p. 418.Google Scholar
11Holland-Moritz, D., Int. J. Non-Equilib. Proc. 11, 169 (1998).Google Scholar
12Schneider, G., Henig, E-Th., Petzow, G., and Stadelmaier, H.H., Z. Metallkd. 77, 755 (1986).Google Scholar
13Zhang, W., Liu, G., and Han, K., J. Phase Equilib. 13, 645 (1992).CrossRefGoogle Scholar
14Hallemans, B., Wollants, P., and Roos, J.R., Z. Metallkd. 85, 676 (1994).Google Scholar
15Eckler, K., Cochrane, R.F., Herlach, D.M., and Feuerbacher, B., Mater. Sci. Eng. A 133, 702 (1991).CrossRefGoogle Scholar
16Kerr, H.W. and Kurz, W., Int. Mater. Rev. 41, 129 (1996).CrossRefGoogle Scholar
17Barth, M., Wei, B., and Herlach, D.M., Phys. Rev. B 51, 3422 (1995).Google Scholar