On the constitution and thermodynamic modelling of the system Ti-Ni-Sn

Author(s)
Matthias Gürth, Andrij Grytsiv, Jan Vrestal, V.A. Romaka, Gerald Giester, Ernst Bauer, Peter Franz Rogl
Abstract

Phase equilibria of the system Ti-Ni-Sn have been determined for the isothermal section at 950 °C based on X-ray powder diffraction (XPD) and electron probe microanalysis (EPMA) of about 60 ternary alloys in as cast and annealed state. The section is characterized by the formation of four ternary compounds labelled τ

1 to τ

4. Whereas two of the ternary compounds are found without significant homogeneity regions: τ

1-TiNiSn (half Heusler phase, MgAgAs-type), τ

3-Ti

2Ni

2Sn (U

2Pt

2Sn-type), τ

4-(Ti

1-x-ySn

xNi

y)Ni

3 with AuCu

3-type exhibits a solution range (0.22 ≤ x ≤ 0.66 and 0.22 ≥ y ≥ 0.02) and a particularly large homogeneity region is recorded for τ

2-Ti

1+yNi

2-xSn

1-y (Heusler phase, MnCu

2Al-type). Extended solid solutions starting from binary phases at 950 °C have been evaluated for Ti

5Ni

1-xSn

3 (filled Mn

5Si

3 = Ti

5Ga

4-type; 0 ≤ x ≤ 1), Ti

1-xSn

xNi

3 (TiNi

3-type; 0 ≤ x ≤ 0.27) and (Ti

1-xNi

x)

1-ySn

y (CsCl-type) reaching a maximum solubility at x = 0.53, y = 0.06). From differential thermal analysis (DTA) in alumina crucibles under argon a complete liquidus surface has been elucidated revealing congruent melting for τ

2-TiNi

2Sn at 1447 °C, but incongruent melting for τ

1-TiNiSn (pseudobinary peritectic formation: ℓ + τ

2 虠 τ

1 at 1180 °C), τ

3-Ti

2Ni

2Sn (peritectic formation: L + τ

2 + Ti

5NiSn

3 虠 τ

3 at 1151 °C) and τ

4-Ti

1-xSn

xNi

3 (peritectic formation: L + TiNi

3 + (Ni) 虠 τ

4 at 1157 °C). A Schultz-Scheil diagram for the solidification behavior was constructed for the entire diagram involving 20 isothermal four-phase reactions in the ternary. For a thermodynamic CALPHAD assessment of the ternary diagram we relied on the binary boundary systems as modelled in the literature. As thermodynamic data in the ternary system were only available in the literature for the compounds TiNi

2Sn and TiNiSn, heat of formation data were supplied by our density functional theory (DFT) calculations for Ti

2Ni

2Sn, as well as for the solid solutions, which were modelled for Ti

1-xSn

xNi

3, Ti

5Ni

1-xSn

3 and (Ti

1-xNi

x)

1-ySn

y. Thermodynamic calculation was performed with the Pandat software and finally showed a reasonably good agreement for all the 20 invariant reaction isotherms involving the liquid.

Organisation(s)
Department of Materials Chemistry, Department of Mineralogy and Crystallography
External organisation(s)
Masaryk University, Lviv Polytechnic National University, Technische Universität Wien
Journal
RSC Advances
Volume
5
Pages
92270-92291
No. of pages
22
ISSN
2046-2069
DOI
https://doi.org/10.1039/c5ra16074j
Publication date
10-2015
Peer reviewed
Yes
Austrian Fields of Science 2012
104017 Physical chemistry, 104011 Materials chemistry, 105113 Crystallography, 104024 X-ray structural analysis
Keywords
ASJC Scopus subject areas
General Chemical Engineering, General Chemistry
Portal url
https://ucrisportal.univie.ac.at/en/publications/2da66e40-10de-445c-aae0-ee9b90a93871