title: Mechanical properties and cytocompatibility of oxygen-modified β-type Ti-Cr alloys for spinal fixation devices.
abstract: In this study, various amounts of oxygen were added to Ti-10Cr (mass%) alloys. It is expected that a large changeable Young's modulus, caused by a deformation-induced ω-phase transformation, can be achieved in Ti-10Cr-O alloys by the appropriate oxygen addition. This "changeable Young's modulus" property can satisfy the otherwise conflicting requirements for use in spinal implant rods: high and low moduli are preferred by surgeons and patients, respectively. The influence of oxygen on the microstructures and mechanical properties of the alloys was examined, as well as the bending springback and cytocompatibility of the optimized alloy. Among the Ti-10Cr-O alloys, Ti-10Cr-0.2O (mass%) alloy shows the largest changeable Young's modulus following cold rolling for a constant reduction ratio. This is the result of two competing factors: increased apparent β-lattice stability and decreased amounts of athermal ω phase, both of which are caused by oxygen addition. The most favorable balance of these factors for the deformation-induced ω-phase transformation occurred at an oxygen concentration of 0.2mass%. Ti-10Cr-0.2O alloy not only exhibits high tensile strength and acceptable elongation, but also possesses a good combination of high bending strength, acceptable bending springback and great cytocompatibility. Therefore, Ti-10Cr-0.2O alloy is a potential material for use in spinal fixture devices.
authors.affiliation: Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan. Electronic address: liuhuihong@imr.tohoku.ac.jp.
authors.forename: Huihong
authors.initials: H
authors.lastname: Liu
authors.affiliation: Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Niinomi
authors.affiliation: Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Nakai
authors.affiliation: Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Cho
authors.affiliation: Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Kengo
authors.initials: K
authors.lastname: Narita
authors.affiliation: Graduate School of Environmental Studies, Tohoku University, Sendai 980-8579, Japan; Department of Biomedical Engineering, Faculty of Engineering and Architecture, Katip Celebi University, Izmir 35620, Turkey.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Şen
authors.affiliation: Graduate School of Environmental Studies, Tohoku University, Sendai 980-8579, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Shiku
authors.affiliation: Graduate School of Environmental Studies, Tohoku University, Sendai 980-8579, Japan; WPI-Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Matsue
mesh_terms: D000497:Alloys; D001672:Biocompatible Materials; D002857:Chromium / Q000737:chemistry*; D008422:Materials Testing; D010100:Oxygen / Q000737:chemistry*; D013131:Spine / Q000601:surgery*; D014025:Titanium / Q000737:chemistry*
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D002857:Chromium; D014025:Titanium; D010100:Oxygen
keywords: Changeable Young’s modulus; Cytocompatibility; Deformation-induced ω phase; Spinal fixation; Titanium alloys