Hostname: page-component-78c5997874-s2hrs Total loading time: 0 Render date: 2024-11-11T02:20:51.480Z Has data issue: false hasContentIssue false
  • English
  • Français

Microstructural evolution in lead-free solder alloys: Part II. Directionally solidified Sn-Ag-Cu, Sn-Cu and Sn-Ag

Published online by Cambridge University Press:  03 March 2011

Sarah L. Allen ,
Michael R. Notis ,
Richard R. Chromik ,
Richard P. Vinci ,
Daniel J. Lewis  and
Robert Schaefer
Sarah L. Allen
Affiliation:
Department of Materials Science and Engineering, Lehigh University, Whitaker Laboratory, 5 East Packer Avenue, Bethlehem, Pennsylvania 18015
Michael R. Notis
Affiliation:
Department of Materials Science and Engineering, Lehigh University, Whitaker Laboratory, 5 East Packer Avenue, Bethlehem, Pennsylvania 18015
Richard R. Chromik
Affiliation:
Department of Materials Science and Engineering, Lehigh University, Whitaker Laboratory, 5 East Packer Avenue, Bethlehem, Pennsylvania 18015
Richard P. Vinci
Affiliation:
Department of Materials Science and Engineering, Lehigh University, Whitaker Laboratory, 5 East Packer Avenue, Bethlehem, Pennsylvania 18015
Daniel J. Lewis
Affiliation:
Metallurgy Division, National Institute of Standards and Technology, Materials Science and Engineering Laboratory, Gaithersburg, Maryland 20899
Robert Schaefer
Affiliation:
Metallurgy Division, National Institute of Standards and Technology, Materials Science and Engineering Laboratory, Gaithersburg, Maryland 20899
Get access

Abstract

The tin–silver–copper eutectic is a three-phase eutectic consisting of Ag3Sn plates and Cu6Sn5 rods in a (Sn) matrix. It was thought that the two phases would coarsen independently. Directionally solidified ternary eutectic and binary eutectic samples were isothermally annealed. Coarsening of the Cu6Sn5 rods in the binary and ternary eutectics had activation energies of 73 ± 3 and 82 ± 4 kJmol-1, respectively. This indicates volume copper diffusion is the rate controlling mechanism in both. The Ag3Sn plates break down and then coarsen. The activation energies for the plate breakdown process were 35 ± 3 and 38 ± 3 kJmol-1 for the binary and ternary samples respectively. This indicates that tin diffusion along the Ag3Sn/(Sn) interfaces is the most likely the rate-controlling mechanism. The rate-controlling mechanisms for Cu6Sn5 coarsening and Ag3Sn plate breakdown are the same in the ternary and binary systems, indicating that the phases evolve microstructurally independently of one another in the ternary eutectic.

Keywords

Directional solidificationAgingKinetics
Type
Articles
Information
Journal of Materials Research , Volume 19 , Issue 5 , May 2004 , pp. 1425 - 1431
Copyright
Copyright © Materials Research Society 2004

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

REFERENCES

1Allen, S.L., Notis, M.R., Chromik, R.R. and Vinci, R.P., Microstructural evolution in lead-free solder alloys: Part I. Cast Sn-Ag-Cu. J. Mater. Res. 19,1417 (2004).Google Scholar
2Moon, K.W., Boettinger, W.J., Kattner, U.R., Biancaniello, F.S. and Handwerker, C.A., Experimental and thermodynamic assessment of Sn-Ag-Cu solder alloys. J. Electron. Mater. 29, 1122 (2000).CrossRefGoogle Scholar
3Lewis, D., Notis, M., Scotch, A. and Allen, S., Determination of the eutectic structure in the Sn-Ag-Cu system. J. Electron. Mater. 31,161 (2002).CrossRefGoogle Scholar
4Walter, J.L. and Cline, H.E., Stability of the directionally solidified eutectics NiAl-Cr and NiAl-Mo. Metall. Trans. 4, 33 (1972).CrossRefGoogle Scholar
5Holmes, W.C. and Hoyt, J.J. in Nucleation and Growth Processes in Materials, edited by Gonis, A., Turchi, P.E.A., and Ardell, A.J. (Mater. Res. Symp. Soc. Proc. 580,Warrendale, PA, 2000), pp 315–320.Google Scholar
6Smartt, H.B. and Courtney, T.H., The kinetics of coarsening in the Al-Al3Ni system. Metall. Trans. A 7A, 123 (1976).CrossRefGoogle Scholar
7Lin, L.Y., Courtney, T.H., The thermal stability of the fibrous copper-chromium eutectic. Metall. Trans. A 7A, 1435 (1976).CrossRefGoogle Scholar
8Lin, L.Y., Courtney, T.H., Stark, J.P. and Ralls, K.M., Fault migration vs. two-dimensional Ostwald ripening as a mechanism for coarsening of rod eutectics. Scr. Metall. 9, 1219 (1975).Google Scholar
9Dyson, B.F., Diffusion of gold and silver in tin single crystals. J. Appl. Phys. 37, 2375 (1966).CrossRefGoogle Scholar
10Dyson, B.F., Thomas, A.R. and Turnbull, D., Interstitial diffusion of copper in tin. J. Appl. Phys. 38, 3408 (1967).CrossRefGoogle Scholar
11Meakin, J.D. and Klokholm, E., Self-diffusion in tin single crystals. Trans. AIME 280, 463 (1960).Google Scholar
12Batha, L., Solubility and mobility of silver in polycrystalline tin. Acta Phys. Chim. Debr. 11, 79 (1965).Google Scholar
13Lange, W. and Bergner, D., Measurement of grain boundary self-diffusion in polycrystalline tin. Phys. Status Solidi 2, 1410 (1962).CrossRefGoogle Scholar
14 U.R. Kattner: Data from thermodynamically evaluated Sn-Ag and Sn-Cu binary phase diagrams (Personal communication, 2002).Google Scholar
15 R. Schaefer and D. Lewis: Directional solidification in a AgCuSn eutectic alloy (unpublished).Google Scholar
16Malzhan, J.C. Kampe, Courtney, T.H. and Leng, Y., Shape instabilities of plate-like structures-I. Experimental observations in heavily cold-worked in situ composites. Acta Metall. 37, 1735 (1989).Google Scholar
17Courtney, T.H. and Malzahn, J.C. Kampe, Shape instabilities of plate-like structures-II. Analysis. Acta Metall. 37, 1747 (1989).CrossRefGoogle Scholar
18Werner, E., Acta Metall. 7, 2047 (1989).CrossRefGoogle Scholar
19Wey, M.Y. and Choi, J.H., The spheroidization of thin plates. J. Korean Inst. Met. Mater. 32, 1269 (1994).Google Scholar
20Wey, M.Y. and Yang, J-M., The effect of alloying elements on the spheroidization of lamellar pearlite. J. Korean Inst. Met. Mater. 32, 1269 (1994).Google Scholar
21Parka, D-Y. and Yang, J-M., Coarsening of lamellar microstructures in directionally solidified yttrium aluminate/alumina eutectic fiber. J. Am. Ceram. Soc. 84, 2991 (2001).CrossRefGoogle Scholar
22Tian, Y.L. and Kraft, R.W., Kinetics of pearlite spheroidization. Metall. Trans. A 18A, 1359 (1987).CrossRefGoogle Scholar
23Chattopadhyay, S. and Sellars, C.M., Quantitative measurements of pearlite spheroidization. Metallography 10, 89 (1977).CrossRefGoogle Scholar
24Atasoy, O.E. and Özbilen, S., Pearlite spheroidization. J. Mater. Sci. 24, 281 (1989).CrossRefGoogle Scholar