Hostname: page-component-5c6d5d7d68-wpx84 Total loading time: 0 Render date: 2024-08-22T01:42:44.688Z Has data issue: false hasContentIssue false
  • English
  • Français

Cast NiTi Shape-Memory Alloys

Published online by Cambridge University Press:  01 February 2011

Alicia M. Ortega ,
Carl P. Frick ,
Jeffrey Tyber ,
Ken Gall  and
Hans J. Maier
Alicia M. Ortega
Affiliation:
Department of Mechanical Engineering, University of Colorado Boulder, CO 80309, U.S.A.
Carl P. Frick
Affiliation:
Department of Mechanical Engineering, University of Colorado Boulder, CO 80309, U.S.A.
Jeffrey Tyber
Affiliation:
Department of Mechanical Engineering, University of Colorado Boulder, CO 80309, U.S.A.
Ken Gall
Affiliation:
Department of Mechanical Engineering, University of Colorado Boulder, CO 80309, U.S.A.
Hans J. Maier
Affiliation:
Lehrstuhl für Werkstoffkunde (Materials Science), University of Paderborn 33095. Paderborn, Germany
Get access

Abstract

The purpose of this study is to investigate the structure and properties of polycrystalline NiTi in its cast form. Although it is commonly stated in the literature that cast NiTi has poor shape-memory behavior, this study demonstrates that with appropriate nano/micro structural design, cast NiTi possesses excellent shape-memory properties. Cast NiTi shape-memory alloys may give rise to a new palette of low-cost, complex-geometry components. Results from two different nominal compositions of cast NiTi are presented: 50.1 at.%Ni and 50.9 at.%Ni. The cast NiTi showed a spatial variance in grain size and a random grain orientation distribution throughout the cast material. However, small variances in the thermo-mechanical response of the cast material resulted. Transformation temperatures were slightly influenced by the radial location from which the material was extracted from the casting, showing a change in Differential Scanning Calorimetry peak diffuseness as well as a change in transformation sequence for the 50.9 at.%Ni material. Mildly aged 50.9 at.%Ni material was capable of full shape-memory strain recovery after being strained to 5% under compression, while the 50.1 at.%Ni demonstrated residual plastic strains of around 1.5%. The isotropic and symmetric response under tensile and compressive loading is a result of the measured random grain orientation distribution. The favorable recovery properties in the cast material are primarily attributed to the presence of nanometer scale precipitates, which inhibit dislocation motion and favor the martensitic transformation.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 855: Symposium W – Mechanically Active Materials , 2004 , W1.8
Copyright
Copyright © Materials Research Society 2005

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Suzuki, Y., in Shape Memory Materials (Eds. Otsuka, K., Wayman, C.M.), Cambridge University Press 1998, 133.Google Scholar
2. Duerig, T.W., Pelton, A.R., Materials Properties Handbook: Titanium Alloys 1994, 1035.Google Scholar
3. Pelton, A.R., Russell, S.M., DiCello, J., Physical Metallurgy 2003, 55, 33.Google Scholar
4. Wang, L.M., Liu, L.H., Yang, H., Wang, L.Y., Xiu, G.Q., Materials Science Forum 2002, 394–395, 297.Google Scholar
5. Civjan, S., Huget, E.F., DeSimon, L.B., Journal of Dental Research 1975, >54, 89.54,+89.>Google Scholar
6. Takahashi, J., Okazaki, M., Kimura, H., Furuta, Y., Journal of Biomedical Materials Research 1984, 18, 427.Google Scholar
7. Takahashi, J., Okazaki, M., Kimura, H., Furuta, Y., Dental Materials Journal 1985, 4, 146.Google Scholar
8. Yoneyama, T., Doi, H., Hamanaka, H., Dental Materials Journal 1992, 11, 157.Google Scholar
9. Yoneyama, T., Doi, H., Kobayashi, E., Hamanaka, H., Journal of Materials Science: Materials in Medicine 2002, 13, 947.Google Scholar
10. Tang, W., Sundman, B., Sandström, R., Qiu, C., Acta Materialia 1999, 47, 3457.Google Scholar
11. Khalil-Allafi, J., Dloughy, A., Eggler, G., Acta Materialia 2002, 50, 4255.Google Scholar
12. Ortega, A.M., Tyber, J., Frick, C.P., Gall, K., and Maier, H.J. (2004), Cast NiTi Shape Memory Alloys, Advanced Engineering Materials, In Press.Google Scholar
13. Gall, K., Sehitoglu, H., International Journal of Plasticity 1999, 15, 69.Google Scholar
14. Saburi, T., in Shape Memory Materials (Eds. Otsuka, K., Wayman, C.M.), Cambridge University Press 1998, 49.Google Scholar
15. Miyazaki, S., No, V.H., Kitamura, K., Khantachawana, A., Hosoda, H., International Journal of Plasticity 2000, 16, 1135.Google Scholar
16. Inoue, H., Miwa, N., Inakazu, N., Acta Materialia 1996, 44, 4825.Google Scholar
17. Mulder, J.H., Thoma, P.E., Beyer, J., Z. Metallkd. 1993, 84, 501.Google Scholar