Effect of Zr Addition on Phase Constitution and Heat Treatment Behavior of Ti-25mass%Nb Alloys


Article Preview

In an attempt to optimize the shape recovery temperature, the effect of Zr addition on phase constitution and heat treatment behavior is investigated by electrical resistivity and Vickers hardness (HV) measurements, X-ray diffractometry (XRD) and shape recovery tests. Ti-25mass%Nb-0, 2, 7 and 12mass%Zr alloys (abbreviated as 0Zr, 2Zr, 7Zr and 12Zr, respectively) were prepared using an arc-furnace. Specimens were solution-treated at 1273 K for 3.6 ks and then quenched by iced water (STQ). STQed specimens were isochronally heat-treated. In 0Zr and 2Zr, only the orthorhombic martensite phase a” was identified by XRD, while the two-phase alloys a” and b were identified in 7Zr and 12Zr. In 7Zr, resistivity at liquid nitrogen and room temperature (rLN and rRT, respectively) and resistivity ratio (rLN/rRT) drastically increased at 523 K because of the reverse-transformation of a” into b phase. Thereafter, resistivity and resistivity ratio decreased with increasing heat treatment temperature due to isothermal w precipitation. Starting temperature of shape recovery is 623 K in 7Zr and 523 K in 12Zr. In 7Zr, shape recovery ratio is about 80% at 723 K, which is the maximum obtained in this study.



Materials Science Forum (Volumes 475-479)

Main Theme:

Edited by:

Z.Y. Zhong, H. Saka, T.H. Kim, E.A. Holm, Y.F. Han and X.S. Xie




M. Ikeda et al., "Effect of Zr Addition on Phase Constitution and Heat Treatment Behavior of Ti-25mass%Nb Alloys", Materials Science Forum, Vols. 475-479, pp. 2337-2342, 2005

Online since:

January 2005




[1] Hukushiyougu・seihinkaihatsu no shin-tenkai, ed. by Tore Research center, (Tore research center, Ltd., Tokyo, 2000) p.5.

[2] H. Kawahara and M. Nakamura: Seitaikei kara mita zairyou-soshiki kaimen no syo seishitsu, Iyou zairyou no kagaku, ed. by Nihon kagaku-kai, (Gakkai syuppan senta, Tokyo, 1978) p.13.

[3] M. Niinomi: Metall, Mater. Trans. A Vol. 33A (2002), p.477.

[4] T. Ahmed, M. Long, J. Silvetri, C. Ruiz and H. J. Rack: Titanium '95: Science and Technology, ed. by P. A. Blenkinsop, W. J. Evans and H. M. Flower, (The Institute of Materials, London, 1996) , p.1760.

[5] D. Kuroda, M. Niinomi, M. Morinaga, Y. Kato and T. Yashiro: Materials Science and Engineering Vol. A243 (1998), p.244.

[6] E. Takahashi, T. Sakurai, S. Watanabe, N. Masahashi and S. Hanada: Materials Transactions Vol. 43 (2002), p.2978.

[7] M. Ikeda, Y. Nakamura and N. Takahama, J. Japan Inst. Metals, Vol. 67 (2003), p.420.

[8] M. Ikeda, S. Komatsu and Y. Nakamura: Mater. Trans., Vol. 43 (2002), p.2984.

[9] H. Sasano and T. Suzuki: Titanium Science and Technology, ed. by G. Luetjering, U. Zwicker and W. Bunk (Deutsche Gesellschaft fuer Metallkunde e. V., Germany 1985), p.1667.