Abstract
The solidification experiment of Al-9.5 wt.% Zn alloy was conducted under both normal gravity and microgravity conditions by using a 50-m-high drop tube. The solidification microstructure was observed by using optical microscope. The amounts, morphologies together with sizes of the grains in the remelting regions on longitudinal sections of the samples were statistically analyzed with the image analysis software. Moreover, the axial and radial composition distributions were studied by applying SEM–EDX. The results show that the remelted solidification structure morphologies of the samples can be roughly divided into three categories, the small equiaxed grains formed by initial chilling, the elongated columnar crystals and the coarse equiaxed grains at the end, but the amount, size and morphology of the grains are different in the samples solidified under the two gravity conditions. The number of grains obtained in μg sample is larger, and the grain size distribution concentrates in small size intervals. Some pores were observed in the small equiaxed grain regions formed at the early stage of solidification in both samples, and several pores were also observed in the coarse equiaxed grain region formed at the later stage of solidification merely in μg sample. In addition, the distributions of solute element in radial and axial direction are more uniform in μg sample, while solute content in 1g sample fluctuates greatly and tends to converge towards the lower part of the sample. The above results suggest that under normal gravity condition, buoyancy convection could lead to the lower temperature gradient and supercooling, which reduced the nucleation rate. Meanwhile, buoyancy could let nuclei float up and melt rich of Zn flow down, and thus promoted grain growth and downwards segregation of Zn solute as well. Besides, buoyancy could drive bubbles to float up and facilitated them to escape from the melt.
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References
Ares, A.E., Schvezov, C.E.: Influence of solidification thermal parameters on the columnar-to-equiaxed transition of aluminum-zinc and zinc-aluminum alloys. Metall. Mater. Trans. a. (2007). https://doi.org/10.1007/s11661-007-9111-z
Boettinger, W.J., Coriell, S.R., Greer, A.L., Karma, A., Kurz, W., Rappaz, M., Trivedi, R.: Solidification microstructures: Recent developments, future directions. Acta. Mater. (2000). https://doi.org/10.1016/S1359-6454(99)00287-6
Bogno, A., Nguyen-Thi, H., Billia, B., Reinhart, G., Mangelinck-Noel, N., Bergeon, N., Schenk, T., Baruchel, J.: In situ and real-time analysis of the growth and interaction of equiaxed grains by synchrotron X- ray radiography. 3rd International Conference on Advances in Solidification Processes. (2012). https://doi.org/10.1088/1757-899x/27/1/012089
Cahoon, J.R., Chaturvedi, M.C., Tandon, K.N.: The unidirectional solidification of Al-4 Wt pct Cu ingots in microgravity. Metall. Mater. Trans. a. (1998). https://doi.org/10.1007/s11661-998-1019-8
Camel, D., Dupouy, M.D.: Comparative study of the Columnar-Equiaxed Transition in microgravity and on ground during directional solidification of a refined Al-3.5 wt% Ni alloy. J. Phys. Iv. (2001). https://doi.org/10.1051/jp4:2001614
Curreri, P.A., Lee, J.E., Stefanescu, D.M.: Dendritic solidification of alloys in low gravity. Metall. Trans. A (1988). https://doi.org/10.1007/BF02645800
Dupouy, M.D., Camel, D., Favier, J.J.: Natural convective effects in directional dendritic solidification of binary metallic alloys: Dendritic array primary spacing. Acta. Metall. Mater. (1992). https://doi.org/10.1016/0956-7151(92)90122-U
Dupouy, M.D., Drevet, B., Camel, D.: Influence of convection on the selection of solidification microstructures at low growth rates. J. Cryst. Growth. (1997). https://doi.org/10.1016/S0022-0248(97)00191-7
Gandin, C.A., Billia, B., Zimmermann, G., Browne, D.J., Dupouy, M.D., Guillemot, G., Nguyen-Thi, H., Mangelinck-Noel, N., Reinhart, G., Sturz, L., Mc Fadden, S., Banaszek, J., Fautrelle, Y., Zaidat, K., Ciobanas, A.: Columnar-to-Equiaxed Transition in SOLidification Processing (CETSOL): a project of the European Space Agency (ESA) - Microgravity Applications Promotion (MAP) programme. Mater. Sci. Forum. (2006). https://doi.org/10.4028/www.scientific.net/MSF.508.39
Hu, H.: Principle of metal solidification. Machine Industry Press, Beijing (2000)
Hu, W., Xu, S.: Microgravity hydromechanics. Science Press, Beijing (1999)
Hu, W., Zhao, J., Long, M., Zhang, X., Liu, Q., Hou, M., Kang, Q., Wang, Y., Xu, S., Kong, W., Zhang, H., Wang, S., Sun, Y., Hang, H., Huang, Y., Cai, W., Zhao, Y., Dai, J., Zheng, H., Duan, E., Wang, J.: Space Program SJ-10 of Microgravity Research. Microgravity Sci. Technol. (2014). https://doi.org/10.1007/s12217-014-9390-0
Kong, Y., Luo, X., Li, Y., Liu, S.: Gravity-induced solidification segregation and its effect on dendrite growth in Al-2.8 Wt.% Cu alloy, Microgravity Sci. Technol. (2021). https://doi.org/10.1016/10.1007/s12217-021-09913-4
Kurz, W., Fisher, D.J.: Fundamentals of solidification. Trans Tech Publications, Florida (1998)
Li, W., Jiang, H., Zhang, L., Li, S., He, J., Zhao, J., Ai, F.: Solidification of Al-Bi-Sn immiscible alloy under microgravity conditions of space. Scr. Mater. (2018). https://doi.org/10.1016/j.scriptamat.2018.12.010
Liu, D.R., Mangelinck-Noel, N., Gandin, C.A., Zimmermann, G., Sturz, L., Thi, H.N., Billia, B.: Structures in directionally solidified Al-7 wt.% Si alloys: Benchmark experiments under microgravity. Acta. Mater. (2014). https://doi.org/10.1016/j.actamat.2013.10.038
Lumley, R.N., Schaffer, G.B.: Anomalous pore morphologies in liquid-phase-sintered Al-Zn alloys. Metall. Mater. Trans. a. (1999). https://doi.org/10.1007/s11661-999-0108-7
Luo, X., Feng, S., Li, Y: Solidification of AlCuMgZn single crystal in space. Chin. J. Space Sci. (2016). https://doi.org/10.11728/cjss2016.04.445
Luo, X., Wang, Y., Li, Y.: Role of hydrostatic pressure and wall effect in solidification of TC8 alloy. NPJ Microgravity. (2019). https://doi.org/10.1038/s41526-019-0083-2
Rappaz, M., Desbiolles, J.L., Gandin, C.A., Henry, S., Semoroz, A., Thevoz, P.: Modelling of solidification microstructures. Solidification and Gravity 2000. (2000). https://doi.org/10.4028/www.scientific.net/MSF.329-330.389
Ratke, L., Genau, A., Steinbach, S.: Flow effects on the dendritic microstructure of AlSi-based alloys. Trans. Indian Inst. Met. (2009). https://doi.org/10.1007/s12666-009-0050-9
Reinhart, G., Gandin, C.A., Mangelinck-Noel, N., Nguyen-Thi, H., Spinelli, J.E., J. Baruchel, J., Billia, B.: Influence of natural convection during upward directional solidification: A comparison between in situ X-ray radiography and direct simulation of the grain structure. Acta. Mater. (2013). https://doi.org/10.1016/j.actamat.2013.04.067
Sato, T., Ito, K., Ohira, G.: Distribution of the interfacial holes at the beginning of the interfacial instability in solidification of Al-Zn alloy. T. Jpn. I. Met. (1980). https://doi.org/10.2320/matertrans1960.21.449
Yamanaka, N., Sakane, S., Takaki, T.: Multi-phase-field lattice Boltzmann model for polycrystalline equiaxed solidification with motion. Comp. Mater. Sci. (2021). https://doi.org/10.1016/J.COMMATSCI.2021.110658
Yeoh, G.H., Davis, G.D., Leonardi, E., De Groh, H.C., Yao, M.: A numerical and experimental study of natural convection and interface shape in crystal growth. J. Cryst. Growth. (1997). https://doi.org/10.1016/S0022-0248(96)00851-2
Zhang, N., Luo, X., Feng, S., Ren, Y.: Mechanism of gravity effect on solidification microstructure of eutectic alloy. J. Mater. Sci. Technol. (2014). https://doi.org/10.1016/j.jmst.2013.11.009
Zhou, Y., Hu, Z., Jie, W.: Solidification technology. Machine Industry Press, Beijing (1998)
Zimmermann, G., Sturz, L., Billia, B., Mangelinck-Noel, N., Thi, H.N., Gandin, C.A., Browne, D.J., Mirihanage, W.U.: Investigation of columnar-to-equiaxed transition in solidification processing of AlSi alloys in microgravity - The CETSOL project. J. Phys. Conf. Ser. (2011). https://doi.org/10.1088/1742-6596/327/1/012003
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This research was supported by the China manned space engineering (TGJZ800-2-RW024).
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This article belongs to the Topical Collection: Research Pioneer and Leader of Microgravity Science in China: Dedicated to the 85th Birthday of Academician Wen-Rui Hu
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Kong, Y., Luo, X., Li, Y. et al. Role of Gravity in Grain and Bubble Morphology Evolution During Solidification of Al-9.5 Wt.% Zn Alloy. Microgravity Sci. Technol. 34, 48 (2022). https://doi.org/10.1007/s12217-022-09951-6
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DOI: https://doi.org/10.1007/s12217-022-09951-6