Effects of Annealing Heat Treatment Conditions on Phase Transformation of Nitinol Shape Memory Alloy

어닐링 열처리 조건에 따른 NITINOL형상기억합금의 상변환 특성 연구

  • 윤성호 (금오공과대학교 기계공학부) ;
  • 여동진 (금오공과대학교 기계공학부 대학원)
  • Published : 2005.04.01

Abstract

Phase transformation behaviors and crystal structures of Nitinol shape memory alloy $(54.5Ni-45.5Tiwt\%)$ are investigated by varying annealing heat treatment conditions through DSC (Differential Scanning Calorimetry) and XRD (X-Ray Diffraction). Annealing heat treatment conditions were considered as heat treated times of 5min, 15min. 30m1n, and 45min, as well as heat treated temperatures of $400^{\circ}C,\;500^{\circ}C,\;525^{\circ}C,\;550^{\circ}C,\;575^{\circ}C,\;600^{\circ}C,\;700^{\circ}C,\;800^{\circ}C,\;and\;900^{\circ}C$ According to the results, annealing heat treatment conditions such as heat treated times and heat treated temperatures were found to affect significantly on phase transformation behaviors and crystal structures of Nitinol shape memory alloy.

본 연구에서는 시차주사열량분석장치와 X-선 회절장치를 이용하여 어닐링 열처리 조건에 따른 니티놀 형상기억합금의 상변환 특성과 결정구조를 조사하였다. 어닐링 열처리 조건으로는 열처리 시간과 열처리 온도를 고려하였으며 특히 열처리 시간은 5분. 15분, 30분, 45분 그리고 열처리 온도는 $400^{\circ}C,\;500^{\circ}C,\;525^{\circ}C,\;550^{\circ}C,\;575^{\circ}C,\;600^{\circ}C,\;700^{\circ}C,\;800^{\circ}C,\;and\;900^{\circ}C$를 적용하였다 연구결과에 따르면 열처리 시간과 열처리 온도 등의 어닐링 열처리 조건은 니티놀 형상기억합금의 상변환 특성과 결정구조에 큰 영향을 미침을 알 수 있었다.

Keywords

References

  1. Duerig, T.W., Melton, K.N., StOckel, D., and Wayman, C.M., Engineering Aspects of Shape Memory Alloys, Butterworth-Heinemann, 1990
  2. Otsuka, K. and Wayman, C.M., Shape Memory Materials. Cambridge University Press, 1998
  3. Funakubo, H., Shape Memory Alloys. Gordon and Breach Science Publishers, 1987
  4. Lin, H.C., Wu, S.K., Chou, T.S., and Kao, H.P., 'The effects of Cold Rolling on the Martensitic transformation of an Equiatomic NiTi Alloy,' Acta Metallurgica et Materialia. Vol. 39, 1991, pp. 2069-2080 https://doi.org/10.1016/0956-7151(91)90177-3
  5. Miyazaki, S., Igo, Y., and Otsuka, K., 'Effects of Thermal Cycling on the Transformation Temperatures of Ti-Ni Alloys,' Acta Metallurgica, Vol. 34, 1986, pp. 2045-2051 https://doi.org/10.1016/0001-6160(86)90263-4
  6. Hwang, C.M. and Wayman, C.W., 'Electron Microscopy Studies of Martensitic Transformations in Ternary TiNiAl Alloys,' Acta Metallurgica, Vol. 17, 1983, pp. 1449-1453 https://doi.org/10.1016/0001-6160(69)90008-X
  7. Duerig, T., Pelton, A., and StOckel, D., 'An Overview of Nitinol Medical Applications,' Materials Science and Engineering, Vol. A273-275, 1999, pp. 149-160
  8. Huang, X. and Liu, Y., 'Effect of Annealing on the Transformation Behavior and Superelasticity of NiTi Shape Memory Alloy,' Scripta Materialia, Vol. 45, 2001, pp. 153-160 https://doi.org/10.1016/S1359-6462(01)01005-3
  9. Yoon, S.H., Krishnan, S., and White, S.R., 'Thermo-mechanical Characterization of High Temperature NITINOL Shape Memory Alloy,' Journal of Korean Society of Precision Engineering, Vol. 19, 2002, pp. 52-59
  10. Uchil J., Mahesh, K.K., and Kumara, K.G., 'Calorimetric Study of the Effect of Linear Strain on the Shape Memory Properties of Nitinol,' Physica B, Vol. 305, 2001, pp. 1-9 https://doi.org/10.1016/S0921-4526(01)00593-2
  11. Liu, Y., Yang, H., and Voigt, A., 'Thermal Analysis of the Effect of Aging on the Transformation Behaviour of Ti-50.9at% Ni,' Materials Science and Engineering, Vol. A360, 2003, pp. 350-355
  12. Cai, W., Murakami, Y., and Otsuka, K., 'Study of R-phase Transformation in a Ti-50.7at%Ni Alloy by In-situ Transmission electron Microscopy Observations,' Materials Science and Engineering, Vol. A273-275, 1999, pp. 186-189
  13. Stroz, D., 'TEM Studies of the R-phase Transformation in a NITI Shape Memory Alloy after Thermomechanical Treatment,' Materials chemistry and Physics, Vol. 9807, 2003, pp. 1-3