Wear characteristics of Ti–Nb–Ta–Zr and Ti–6Al–4V alloys for biomedical applications

doi:10.1016/j.wear.2004.04.001

Wear

Volume 257, Issues 9–10, November 2004, Pages 869-876

https://doi.org/10.1016/j.wear.2004.04.001 Get rights and content

Abstract

The influences of heat treatment, variation in Nb content, surface modification and counterface materials on the wear characteristics of new β type Ti–Nb–Ta–Zr alloys and conventional metallic implant alloy Ti–6Al–4V were investigated, using a reciprocal pin-on-disc wear device in a 0.9% NaCl solution. For the wear test of sliding on stainless steel disc, experimental results show that the wear resistance of Ti–29Nb–13Ta–4.6Zr and Ti–6Al–4V is insensitive to their mechanical properties, such as hardness and ultimate tensile strength. Increase in Nb content results in an improvement of the wear resistance of the β type alloy to some degree. The wear resistance of Ti–29Nb–13Ta–4.6Zr improved significantly after oxidation treatment, due to the presence of Nb₂O₅ oxide particles on the diffusion hardened surface of the alloy. For wear test of sliding on ultra-high molecular weight polyethylene (UHMWPE) and bone of pig, the wear losses of both Ti–Nb–Ta–Zr and Ti–6Al–4V are much less compared with that sliding on stainless steel and there is almost no wear on the surface of oxided Ti–29Nb–13Ta–4.6Zr.

Introduction

The combination of good mechanical properties and biochemical compatibility makes titanium alloys a desirable class of implant materials for orthopedic applications [1], [2]. However, the elastic modulus of bio-titanium alloys currently in use is still not ideal compared with that of human bone, which may lead to premature failure of the implant.

From the viewpoint of biomechanical compatibility, maximum permissible strain (strength to modulus ratio) is desirable, so an ideal material should have high strength but low modulus. The β phase titanium alloy is known to have lower elastic modulus than the α type or two-phase titanium alloys. The theoretical studies of Song et al. [3], [4] suggest that Zr, Nb, Mo, Hf or Ta may increase the strength and decrease the modulus of bcc Ti. To reduce the toxicity of implant, Nb, Mo, Hf and Ta, were the most suitable elements for titanium alloys. These considerations dictate that biomedical titanium alloys developed recently mainly consist of Ti, Nb, Ta and Zr [5], [6], [7], [8].

Wear characteristics constitute another aspect of the performance of biomedical alloys. Failure generally occurs due to excessive wear of the components. The accumulation of wear debris may produce an adverse cellular response leading to inflammation, release of damaging enzymes, osteolysis, infection, implant loosening and pain [9], [10]. The common approaches used to improve wear resistance of materials include surface modification, adjustment of alloy composition and heat treatment [11], [12], [13], [14], [15], [16].

A new alloy, Ti–29Nb–13Ta–4.6Zr, has recently been developed for biomedical application [6]. This alloy possesses low modulus and low strength under the condition of solution treatment followed by quenching (STQ). In this work, the influence of Nb content, heat treatment, surface modification and counterface materials on the wear properties of the Ti–Nb–Ta–Zr alloy was studied using reciprocal pin-on-disc type wear tests and the results will be compared with the wear properties of a two-phase alloy Ti–6Al–4V.

Section snippets

Materials

Ti–29Nb–13Ta–4.6Zr (wt.%, the alloy is abbreviated as TNZT below) ingot with a diameter of 60 mm was fabricated by induction skull melting method using pure Ti, Nb, Ta and Zr as raw materials and then hot forged to rods with a diameter of 20 mm. In order to investigate the influence of Nb content on the wear characteristics of this alloy family, Ti–39Nb–13Ta–4.6Zr (wt.%, the alloy is abbreviated as THNZT below), was prepared from pure Ti, Nb, Ta and Zr by first melting in an electron beam furnace

Microstructure

After solution treatment at 850 °C for 30 min (scheme TNZT1 in Table 2), a small amount of α″ martensite particles precipitated from the metastable β matrix (Fig. 2a). The height ratio of the X-ray diffraction peaks (1 1 1)α″ to (1 1 0)β is 0.04. The microstructure of the high Nb alloy after identical solution treatment (scheme THNZT1 in Table 2) consists of equiaxed β (Fig. 2b). Subsequent ageing at 500 °C for 24 h (scheme TNZT2 in Table 2) resulted in the massive precipitation of needle-like α phase

Conclusions

(1)
The wear losses of Ti–29Nb–13Ta–4.6Zr and Ti–6Al–4V are insensitive to mechanical properties, such as hardness and ultimate tensile strength. Heat treatment that improves the mechanical properties of alloys is not a practical way to improve the wear resistance of these titanium alloys.
(2)
Increase in Nb content improves the wear resistance of Ti–29Nb–13Ta–4.6Zr to some degree.
(3)
Oxidation treatment of Ti–29Nb–13Ta–4.6Zr greatly improves its wear resistance, due to the formation of a hard, lubricating

Acknowledgements

The research was partially sponsored by Chinese MoST Grant TG2000067105 and NSFC Grant 50128101. The work of SJL at Toyohashi was supported by a visiting studentship from the Japanese Ministry of Education and Culture. MN wishes to acknowledge partial support from NEDO and JSPS. The authors would like to thank Professor S.Z. Li for helpful discussion of some of the results presented in this paper.

References (26)

G.R. Parr et al.
J. Prosthet. Dent
(1985)
Y. Song et al.
Mater. Sci. Eng
(1999)
M. Long et al.
Biomaterials
(1998)
M. Niinomi
Mater. Sci. Eng
(1998)
C. Allen et al.
Wear
(1981–1982)
P.E. Grobler et al.
Wear
(1990)
K. Marcus et al.
Wear
(1991)
F.H. Silver, Biomaterials, Medical Devices and Tissue Engineering: An Integrated Approach, Chapman & Hall, London,...
Y. Song, R. Yang, Z.X. Guo, D. Li, in: M. Niinomi, D.R. Lesuer, T. Okabe, H.E. Lippard, E.M. Taleff (Eds.), Structural...
K. Mishra, J.A. Davidson, R.A. Poggie, P. Kovacs, T.J. Fitzgerald, in: J.E. Lemons (Ed.), Medical Application of...

X. Tang et al.

J. Mater. Sci

(2000)

J. Black, Biological Performance of Materials-Fundamentals of Biocompatibility, second ed., Marcel Dekker Inc., New...

M. Jasty

J. Appl. Biomater

(1993)

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Wear characteristics of Ti–Nb–Ta–Zr and Ti–6Al–4V alloys for biomedical applications

Abstract

Introduction

Section snippets

Materials

Microstructure

Conclusions

Acknowledgements

J. Prosthet. Dent

Mater. Sci. Eng

Biomaterials

Mater. Sci. Eng

Wear

Wear

Wear

J. Mater. Sci

J. Appl. Biomater