| Title |
Effect of Fe Composition and Heat Treatment Temperature on the Transformation Temperature of R-Phase of Ti-Ni-Fe Alloy |
| Authors |
김원석(Wonseok Kim); 금나영(Nayoung Keum); 김진용(Jinyoung Kim); 김재일(Jaeil Kim) |
| DOI |
https://doi.org/10.3365/KJMM.2024.62.4.251 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
Shape memory alloy; heat treatment temperature; R phase transformation; ternary system; Ti-Ni-Fe |
| Abstract |
R-phase transformations in TiNi shape memory alloys (Nitinol) have various applications because of their small thermal hysteresis and low fatigue resistance. Adding a third element such as Fe or Al is one of the useful ways to induce R-phase transformation. Controlling the R-phase transformation temperature is crucial for industrial and bio-field applications. However, the effects of adding Fe have rarely been reported. In this study, the effects of Fe addition and heat treatment temperature on the Rphase transformation temperature of TiNiFe shape memory alloys were systematically investigated. Results showed that increasing Fe composition decreases the R-phase and martensitic transformation temperatures of 19K/1at%Fe and 51 K/1at%Fe, respectively. Additionally, in the Ti-49Ni-1Fe alloy, rather than a martensite transformation, the R phase transformation temperature was constant irrespective of heat treatment temperature and increasing number of thermal cycles. This means that the R-phase transformation temperature is not affected by dislocation density resulting from the heat cycling or cold working processes. This allows practical applications of R-phase transformation to be easily realized. Furthermore, this means that the R-phase transformation temperature is only affected by the Ni content of the matrix.(Received 6 October, 2023; Accepted 28 December, 2023) |