Abstract

MASHAMAITE, M.; NGOEPE, P.  and  CHAUKE, H.. Phase stability of TiPtZr shape memory alloys using cluster expansion techniques. S. Afr. J. Ind. Eng. [online]. 2022, vol.33, n.3, pp.284-289. ISSN 2224-7890.  http://dx.doi.org/10.7166/33-3-2807.

Titanium-Platinum (TiPt) has a martensitic transformation of about 1300 K, making it potential material for use as a high-temperature shape memory alloy. A third element is expected to improve the properties of TiPt alloys for future use in the aerospace industry. In this study, the effect of the addition of Zr on the stability of TiPt was investigated using the cluster expansion method employing the UNCLE code. A total of 21 new structures on the Pt site and 22 new structures on the Ti site were generated. Only seven (7) structures constituted the ground-state line for the Pt site, and six (6) structures for the Ti site, which suggested that these structures were the most thermodynamically stable phases. The ZrTi2Pt phase was the most thermodynamic stable with heats of a formation value of - 0.455 eV/atom on the Pt site. Thus, a phase diagram for the TiPtZr system was constructed. The findings of this study could benefit the design of new materials in the aerospace industry.

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