TY - GEN
T1 - Bending fatigue and spring back properties of implant rods made of β-type titanium alloy for spinal fixture
AU - Narita, Kengo
AU - Niinomi, Mitsuo
AU - Nakai, Masaaki
AU - Akahori, Toshikazu
AU - Tsutsumi, Harumi
AU - Oribe, Kazuya
PY - 2010
Y1 - 2010
N2 - Implanting a spinal fixture using metallic rods is one of the effective treatments for spinal diseases. Because cyclic bending stress is loaded on the implant rods when patients move their upper bodies in daily life, bending fatigue properties are important for the implant rod. Further, the implant rods are bended plastically into a curved shape of spine by hand in a surgical operation. In that case, keeping shape is important, namely bending spring back properties are important factors. On the other hand, a biomedical β-type titanium alloy, Ti-29Nb-13Ta-4.6Zr (mass %) alloy (TNTZ), has been developed by the authors. Currently, this alloy are investigated to be applied to the above mentioned implant rod practically. Therefore, four-point bending fatigue and three point-bending spring back properties of TNTZ subjected various heat treatments were examined in this study. TNTZ rods were subjected to solution treatment, and then some of them were subjected to aging treatment at 673 K or 723 K for 259.2 ks, followed by water quenching. Then, four-point bending fatigue and three-point bending spring back tests were carried out on TNTZ rods subjected to the various heat treatments mentioned above. The bending fatigue strength at 2.5 million cycles in the high cycle fatigue region are not much different among any TNTZ rod. However, the bending fatigue strength of the Ti-6Al-4V ELI (Ti64) rod exceeds the fatigue strengths of every TNTZ rods in both low and high cycle fatigue regions. On the other hand, the lower spring back, which is a favorable property, was obtained for some TNTZ rod than Ti64 rod.
AB - Implanting a spinal fixture using metallic rods is one of the effective treatments for spinal diseases. Because cyclic bending stress is loaded on the implant rods when patients move their upper bodies in daily life, bending fatigue properties are important for the implant rod. Further, the implant rods are bended plastically into a curved shape of spine by hand in a surgical operation. In that case, keeping shape is important, namely bending spring back properties are important factors. On the other hand, a biomedical β-type titanium alloy, Ti-29Nb-13Ta-4.6Zr (mass %) alloy (TNTZ), has been developed by the authors. Currently, this alloy are investigated to be applied to the above mentioned implant rod practically. Therefore, four-point bending fatigue and three point-bending spring back properties of TNTZ subjected various heat treatments were examined in this study. TNTZ rods were subjected to solution treatment, and then some of them were subjected to aging treatment at 673 K or 723 K for 259.2 ks, followed by water quenching. Then, four-point bending fatigue and three-point bending spring back tests were carried out on TNTZ rods subjected to the various heat treatments mentioned above. The bending fatigue strength at 2.5 million cycles in the high cycle fatigue region are not much different among any TNTZ rod. However, the bending fatigue strength of the Ti-6Al-4V ELI (Ti64) rod exceeds the fatigue strengths of every TNTZ rods in both low and high cycle fatigue regions. On the other hand, the lower spring back, which is a favorable property, was obtained for some TNTZ rod than Ti64 rod.
KW - Bending property
KW - Biomaterial
KW - Four-point bending fatigue strength
KW - Spring back
KW - Titanium alloy
UR - http://www.scopus.com/inward/record.url?scp=75749114806&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=75749114806&partnerID=8YFLogxK
U2 - 10.4028/www.scientific.net/AMR.89-91.400
DO - 10.4028/www.scientific.net/AMR.89-91.400
M3 - Conference contribution
AN - SCOPUS:75749114806
SN - 0878492933
SN - 9780878492930
T3 - Advanced Materials Research
SP - 400
EP - 404
BT - THERMEC 2009 Supplement
T2 - 6th International Conference on Processing and Manufacturing of Advanced Materials - THERMEC'2009
Y2 - 25 August 2009 through 29 August 2009
ER -