Abstract
The microstructure of Pd77.5Au6Si16.5alloy solidified both on board a Chinese Retrievable Satellite and on the earth is studied. Postmortem analyses of microstructure presented that the same types of phases, primary phase (Pd3Si) and eutectics (Pd3Si + Pd solid solution) were formed in both cases. But the phase morphologies were quite different. It was dendritic for the primary phase and lamellar for the eutectics under normal gravity condition. However, under microgravity condition the primary phase was granular and the eutectic was peculiar network. Detailed analysis showed that the differences in morphologies of the microstructure were due to the existence of gravity-induced buoyancy convection on the earth which increased the mass transport abilities and decreased the thickness of the solute boundary in front of the solid-liquid interface during solidification under normal gravity condition.
Similar content being viewed by others
References
Rex, S., Convective aspects of solidification experiments under low gravity, inInteractive Dynamics of Convection and Solidification (ed. Davis, S. H.), Netherlands: Kluwer Academic Publishers, 1992, 159–193.
Glicksman, M. E., Koss, M. Winsa, E.A., The chronology of a microgravity spaceflight experiment: IDGE,JOM, 1995, 47(8): 49.
Nguyen Thi, H., Li, Q., Billia, B. et al., Preliminary results of D-2 MEDEA-DENSO experiments on directional solidification of Al-Li alloys, inProceeding of the Norderney Symposium on Scientific Results of the German Spacelab Mission D-2, Norderney, Germany, March, 1994, 379–385.
Stehle, M., Rex, S., Controlled mass transport during directional solidification experiments of a thermosolutally unstable CuMn alloy, inProceeding of the Norderney Symposium on Scientific Results of the German Spacelab Mission D-2, Norderney: DCR, 1994, 386–393.
Liu, R. P., Sun, L. L., Zhao, J. H. et al., Evaluation of effective mass transport coefficients trough comparison of solidification on the ground and on board a satellite,Appl. Phys. Lett., 1997, 71: 64.
Liu, R. P., Sun, L. L., Wang, W. K. et al., Solidification characteristics of Pd40Ni40P20 alloy under microgravity condition,Science in China, Ser. A, 1997, 40: 662.
Rex, S., Solidification: A multidisciplinary and stimulating microgravity research field to get over barriers of materials production, inProceeding of the Norderney Symposium on Scientific Results of the German Spacelab Mission D-2, Norderney, Germany, March, 1994, 359–365.
Steinberg, J., Lacy, L. L., John, J., Production of bulk amorphous Pd77.5CuuSi16.5 in a containerless low-gravity environment,Appl. Phys. Lett., 1981, 38: 135.
Chen, H. S., Miller, C. E., A rapid quenching technique for the preparation of thin uniform films of amorphous solids,Rev. Sci. Instr., 1970, 41: 1237.
Sun, L. L., Wu, Q., Wang, W. K., Decomposition of metastable phase and formation of amorphous silicon in Pd77.5Au6Si16.5 Alloy,J. Mat. Sci. Lett., 1996, 15: 922.
Mao, Z. L., Wang, W. K., Phase formation in drop-tube processing from undercooled PdAuSi melt,J. Mater. Sci., 1993, 28: 4 850.
Sun, L. L., Wu, Q., Wang, W. K., Microstructure of PdAuSi alloy droplet solidified in a drop-tube processing,J. Mater. Sci. Technol., 1996, 12: 385.
Liu, R. P.,Ph. D. Dissertation (in Chinese), Beijing: Institute of Physics, Chinese Academy of Sciences, 1998, 45–80.
Hu, H. Q.,Metal Solidification (in Chinese), Beijing: Metallurgical Industrial Press, 1985, 149–214.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Liu, R., Zhao, J., Zhang, X. et al. Differences in microstructure of Pd77.5Au6Si16.5 alloy solidified under microgravity and gravity conditions. Sci. China Ser. A-Math. 42, 74–79 (1999). https://doi.org/10.1007/BF02872052
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02872052