Thermodynamic study of the phase equilibria in the Sn-Ti-Zn ternary system

K. Doi, S. Ono, H. Ohtani, M. Hasebe

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

The Sn-Ti-Zn ternary phase diagram has been constructed using the CALPHAD technique. The Ti-Zn binary system phase boundaries were determined using differential scanning calorimetry and the solid-liquid diffusion couples method. In addition, the formation energy of some stoichiometric compounds was obtained using first-principle band energy calculations. For the ternary system, some alloys were prepared by equilibration at 600 or 700°C, and the compositions of the precipitates were analyzed using electron probe microanalysis. Thermodynamic assessment of the Ti-Zn and Sn-Ti-Zn systems was performed based on the experimental information and by adopting reported values of the thermodynamic properties of the Sn-Zn and Sn-Ti binary systems. Microstructural observation showed that Sn 3Ti 5Zn 12 exists in the ternary system. Seven types of invariant reaction on the Sn-rich liquidus surface of the ternary system are predicted by the phase diagram calculations. The ternary eutectic point falls at 0.0009 mass% Ti and 8.69 mass% Zn, at T = 192.40°C, which is slightly lower than the calculated eutectic point of Sn-Zn binary alloy (T= 192.41°C). Based on these results, a nonequilibrium solidification process using the Scheil model was simulated.

Original languageEnglish
Pages (from-to)63-74
Number of pages12
JournalJournal of Phase Equilibria and Diffusion
Volume27
Issue number1
DOIs
Publication statusPublished - 2006 Feb 1
Externally publishedYes

Keywords

  • Lead-free solders
  • Liquidus surface
  • Phase diagram
  • Surface tension
  • Thermodynamic analysis

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Metals and Alloys
  • Materials Chemistry

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