Microstructural Development in Pb-Sn Alloys Subjected to High-Gravity during Controlled Directional Solidification
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Research conducted over the past three decades has suggested that solidification processing of metals and alloys in a centrifuge can lead to enhanced materials properties.1-11 With the potential of such processing demonstrated, there exists a need for quantitative data gathered under controlled solidification conditions. To this end, a centrifuge, dedicated to materials research, was constructed within the Materials Science and Engineering Department at Vanderbilt University. This has since been employed to investigate the effect of a high-gravity environment on microstructural development of Pb- 50 wt pct Sn alloys during controlled directional solidification.
For otherwise constant solidification processing conditions of composition, growth rate, and temperature gradient, centrifugation caused the primary dendrite arm spacing to decrease significantly. The secondary dendrite arm spacing, the eutectic spacing, and the primary dendrite trunk diameters exhibited no change with increasing gravity level.
These results are discussed in terms of suppressing convection in the bulk liquid and/or modification of the solute-enriched liquid layer about the dendrite tips. Work in progress to directly visualize effects attributed to enhanced gravity is discussed.
KeywordsBulk Liquid Primary Dendrite Gravity Level Eutectic Spacing Enhance Material Property
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- 11.L.L. Regel, M. Rodot and W.R. Wilcox, eds., “Material Processing in High Gravity,” (1992).Google Scholar
- 12.M. McLean. “Directionally Solidified Materials for high Temperature Service,” The Metals Society (1983).Google Scholar
- 14.C. Battaile, Masters Thesis, Vanderbilt University, Dept. of Materials Science and Engineering (1992).Google Scholar
- 15.C. Battaile, R.N. Grugel, A.B. Hmelo and T.G. Wang in: “Microstructural Design by Solidification Processing,” E. J. Lavernia and N.N. Gungor, eds., The Minerals, Metals and Materials Society (1992) pp 161–172.Google Scholar
- 17.C. Battaile, R.N. Grugel, A.B. Hmelo and T.G. Wang: Submitted to Metallurgical Trans. A.Google Scholar
- 21.J.D. Hunt, “Solidification and Casting of Metals,” Book 192, The Metals Society, London (1979) pp 3–9.Google Scholar
- 23.G. Frohberg, K.H. Kraatz and H. Wever in: “Scientific Results of the German Spacelab Mission D1,” P.R Sahm, R. Jensen and M.H. Keller, eds., WPF, (1986) pp 144–151.Google Scholar
- 27.W. Kurz and R.N. Grugel. “Materials Science Forum,” Trans Tech. Publications, Switzerland (1991) pp 185–204.Google Scholar