Abstract
The magnetic Fe–6.5 wt% Si powder was produced by gas atomization and its microstructure was also investigated. The secondary dendritic arm spacing (SDAS) is related to the droplet size, λ = 0.29 · D0.5, and the numerical solidification model was applied to the system, giving rise to the correlation of microstructure to the solidification process of the droplet. It is found that the solid fraction at the end of recalescence is strongly dependent on the undercooling achieved before nucleation; the chances for the smaller droplets to form the grain-refined microstructures are less than the larger ones. Furthermore, the SDAS is strongly influenced by the cooling rate of post-recalescence solidification, and the relationship can be expressed as follows, \(\lambda = 74.2 \cdot {\left({\dot T} \right)^{- 0.347}}\). Then, the growth of the SDAS is driven by the solute diffusion of the interdendritic liquids, leading to a coarsening phenomenon, shown in a cubic root law of local solidification time, \(\lambda = 10.73 \cdot {\left({{t_f}} \right)^{0.296}}\).
We’re sorry, something doesn't seem to be working properly.
Please try refreshing the page. If that doesn't work, please contact support so we can address the problem.
References
K.I. Arai and K. Ishiyama: Recent developments of new soft magnetic materials. J. Magn. Magn. Mater. 133(1–3), 233 (1994).
Y. Takada, M. Abe, S. Masuda, and J. Inagaki: Commercial scale production of Fe-6.5 wt. % Si sheet and its magnetic properties. J. Appl. Phys. 64(10), 5367 (1988).
T. Yamaji, M. Abe, Y. Takada, K. Okada, and T. Hiratani: Magnetic properties and workability of 6.5% silicon steel sheet manufactured in continuous CVD siliconizing line. J. Magn. Magn. Mater. 133(1–3), 187 (1994).
K.I.A.N. Tsuya: Ribbon-form silicon-iron alloy containing around 6.5 percent silicon. IEEE Trans. Mag. 16(1), 4 (1980).
A.H. Kasama, A.J.J. Moreira, F°.W.J. Botta, C.S. Kiminami, and C. Bolfarini: Influence of the atomization gas on the microstructure and magnetic properties of spray-formed Fe–3%Si–3.5%Al alloys. Mater. Sci. Eng., A 477(1–2), 9 (2008).
H. Shokrollahi and K. Janghorban: Soft magnetic composite materials (SMCs). J. Mater. Process. Technol. 189(1–3), 1 (2007).
G.A.V. Sowter: Soft magnetic materials for audio transformers: History, production, and applications. J. Audio Eng. Soc. 35, 760 (1987).
E. Bayraml, Ö. Gölgelioğlu, and H.B. Ertan: Powder metal development for electrical motor applications. J. Mater. Process. Technol. 161(1–2), 83 (2005).
N. Tiedje, P.N. Hansen, and A.S. Pedersen: Modeling of primary and secondary dendrites in a Cu-6 wt pct Sn alloyMetall. Mater. Trans. A 27(12), 4085 (1996).
A. Freyberg, M. Buchholz, V. Uhlenwinkel, and H. Henein: Droplet solidification and gas-droplet thermal coupling in the atomization of a Cu-6Sn alloy. Metall. Mater. Trans. B 34(2), 243 (2003).
C.G. Levi and R. Mehrabian: Microstructures of rapidly solidified aluminum alloy submicron powders. Metall. Mater. Trans. A 13(1), 13 (1982).
W.J. Boettinger, L. Bendersky, and J.G. Early: An analysis of the microstructure of rapidly solidified Al-8 wt pct Fe powder. Metall. Trans. A 17(5), 781 (1986).
R. Xu, Y.Y. Cui, D. Li, D.M. Xu, Q.C. Li, and Z.Q. Hu: Solidification microstructure of super-α2 alloy prepared by gas atomization. J. Mater. Sci. 32(14), 3821 (1997).
B. Zheng, Y. Lin, Y. Zhou, and E. Lavernia: Gas atomization of amorphous aluminum powder: Part II. Experimental investigation. Metall. Mater. Trans. B 40(6), 995 (2009).
S. Li, P. Wu, H. Fukuda, and T. Ando: Simulation of the solidification of gas-atomized Sn-5mass%Pb droplets. Mater. Sci. Eng., A 499(1–2), 396 (2009).
C.G. Levi and R. Mehrabian: Heat-flow during rapid solidification of undercooled metal droplets. Metall. Trans. A 13(2), 221 (1982).
E.J. Lavernia, E.M. Gutierrez, J. Szekely, and N.J. Grant: A mathematical model of the liquid dynamic compaction process. Part 1: Heat flow in gas atomization. Int. J. Rapid Solidification 4, 89 (1988).
E. Gutierrez-Miravete, E.J. Lavernia, G.M. Trapaga, J. Szekely, and N.J. Grant: A mathematical model of the spray deposition process. Metall. Trans. A 20(1), 71 (1989).
P. Mathur, D. Apelian, and A. Lawley: Analysis of the spray deposition process. Acta Metall. 37(2), 429 (1989).
E-S. Lee and S. Ahn: Solidification progress and heat transfer analysis of gas-atomized alloy droplets during spray forming. Acta Metall. Mater. 42(9), 3231 (1994).
D. Bergmann, U. Fritsching, and K. Bauckhage: A mathematical model for cooling and rapid solidification of molten metal droplets. Int. J. Therm. Sci. 39(1), 53 (2000).
N.H. Pryds and J.H. Hattel: Spray forming: A numerical investigation of the influence of the gas to melt ratio on the billet surface temperature. Int. J. Therm. Sci. 44(6), 587 (2005).
R. Heringer, C.A. Gandin, G. Lesoult, and H. Henein: Atomized droplet solidification as an equiaxed growth model. Acta Mater. 54(17), 4427 (2006).
N. Zeoli, S. Gu, and S. Kamnis: Numerical modelling of metal droplet cooling and solidification. Int. J. Heat Mass Transfer 51(15–16), 4121 (2008).
B. Zheng, Y. Lin, Y. Zhou, and E. Lavernia: Gas atomization of amorphous aluminum: Part I. Thermal behavior calculations. Metall. Mater. Trans. B 40(5), 768 (2009).
H. Okamoto: Phase Diagrams for Binary Alloys, 2nd ed. (ASM International, 2000).
R. Trivedi and K. Somboonsuk: Constrained dendritic growth and spacing. Mater. Sci. Eng. 65(1), 65 (1984).
J.P. Hirth: Nucleation, undercooling and homogeneous structures in rapidly solidified powders. Metall. Trans. A 9(3), 401 (1978).
W. Kurz and D.J. Fisher: Fundamentals of Solidification, 4th ed. (Trans. Tech. Publications, 1998).
K-C. Chang and C-M. Chen: Revisiting heat transfer analysis for rapid solidification of metal droplets. Int. J. Heat Mass Transfer 44(8), 1573 (2001).
D. Turnbull and R.E. Cech: Microscopic observation of the solidification of small metal droplets. J. Appl. Phys. 21(8), 804 (1950).
D.M. Herlach, K. Eckler, A. Karma, and M. Schwarz: Grain refinement through fragmentation of dendrites in undercooled melts. Mater. Sci. Eng., A 304–306(0), 20 (2001).
N.H. Pryds and A.S. Pedersen: Rapid solidification of martensitic stainless steel atomized droplets. Metall. Mater. Trans. A 33(12), 3755 (2002).
T.Z. Kattamis and M.C. Flemings: Dendrite morphology, microsegregation, and homogenization of low-alloy steel. Trans. Metall. Soc. AIME 223, 8 (1965).
S.P. Marsh and M.E. Glicksman: Overview of geometric effects on coarsening of mushy zones. Metall. Mater. Trans. A 27(3), 557 (1996).
ACKNOWLEDGMENT
Appreciation is expressed to Dr. W. Löser for many valuable discussions and for his constructive comments on the manuscript. The authors would like to acknowledge the financial support received from China National Natural Science Foundation (No. 51074104), China National Basic Research Development Project (973 Program: No. 2010CB630802), and Innovation and Creativity Fund of Shanghai University. Instrumental Analysis & Research Center of Shanghai University provided facility for the study of the microstructures.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Li, K., Song, C., Zhai, Q. et al. Microstructure evolution of gas-atomized Fe–6.5 wt% Si droplets. Journal of Materials Research 29, 527–534 (2014). https://doi.org/10.1557/jmr.2014.12
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1557/jmr.2014.12