Fatigue properties of beta-type titanium alloy for biomedical applications under various fatigue conditions

T. Akahori, M. Niinomi, Hiroyuki Toda, H. Fukui, H. Ogawa

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Tensile, plain and notch fatigue properties of a β-type titanium alloy, Ti-29Nb-13Ta-4.6Zr (TNTZ), which was subjected to various thermomechanical treatments, were investigated in order to judge its potential for biomedical applications. Microstructures of TNTZ aged at 723 K for 259.2 ks after cold rolling and those aged at 723 K for 259.2 ks after solution treatment are composed of a precipitated a phase in the β phase. However, microstructures of TNTZ aged at 598 and 673 K for 259.2 ks after cold rolling and aged at 598 K and 673 K for 259.2 ks after solution treatment are composed of a precipitated ω phase and precipitated α and ω phases in the β phase, respectively. Futher, the tensile strengths of TNTZ aged after solution treatment and those aged after cold rolling decrease with an increase in the aging temperature, although the elongation shows the reverse trend. TNTZ composed of the ω phase or the ω and a phases in the β phase shows a tensile strength of arout 1000 MPa or more. On the other hand, plain fatigue strengths of TNTZ aged after solution treatment and those of TNTZ aged after cold rolling increase with the aging temperature. In particular, TNTZ aged at 723 K after cold rolling exhibits the highest fatigue strength in both the low- and high-ycle fatigue life regions. Futher, the fatigue limit, which is about 770 MPa, is nearly equal to that of hot-rolled Ti-6Al-4V ELI conducted with aging, which is one of the representative α+β-type titanium alloys for biomedical applications. The notch fatigue strengths of TNTZ aged at stress concentration factors of 2 and 6 decrease by 30%-40% and 50%-60%, respectively, as compared with the plain fatigue strengths in the low-cycle fatigue life region. Futher, the notch fatigue limits range from 450 to 490 MPa and from 220 to 300 MPa, respecitvely; an exception to this is TNTZ aged at 598 K after cold rolling, which has a high volume fraction of the ω phase. Single- and multi- fatigue cracks initiate at the bottom of the notch at stress concentration factors of 2 and 6, respectively.

Original languageEnglish
Title of host publicationMedical Device Materials III - Proceedings of the Materials and Processes for Medical Devices Conference 2005
Pages154-162
Number of pages9
Volume2006
Publication statusPublished - Dec 1 2006
Externally publishedYes
EventMaterials and Processes for Medical Devices Conference 2005 - Boston, MA, United States
Duration: Nov 14 2006Nov 16 2006

Other

OtherMaterials and Processes for Medical Devices Conference 2005
CountryUnited States
CityBoston, MA
Period11/14/0611/16/06

All Science Journal Classification (ASJC) codes

  • Engineering(all)

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  • Cite this

    Akahori, T., Niinomi, M., Toda, H., Fukui, H., & Ogawa, H. (2006). Fatigue properties of beta-type titanium alloy for biomedical applications under various fatigue conditions. In Medical Device Materials III - Proceedings of the Materials and Processes for Medical Devices Conference 2005 (Vol. 2006, pp. 154-162)