Beta type Ti-Mo alloys with changeable Young's modulus for spinal fixation applications

Xingfeng Zhao, Mitsuo Niinomi, Masaaki Nakai, Junko Hieda

Research output: Contribution to journalArticlepeer-review

137 Citations (Scopus)


To develop a novel biomedical titanium alloy with a changeable Young's modulus via deformation-induced ω phase transformation for the spinal rods in spinal fixation devices, a series of metastable β type binary Ti-(15-18)Mo alloys were prepared. In this study, the microstructures, Young's moduli and tensile properties of the alloys were systemically examined to investigate the effects of deformation-induced ω phase transformation on their mechanical properties. The springback of the optimal alloy was also examined. Ti-(15-18)Mo alloys subjected to solution treatment comprise a β phase and a small amount of athermal ω phase, and they have low Young's moduli. All the alloys investigated in this study show an increase in the Young's modulus owing to deformation-induced ω phase transformation during cold rolling. The deformation-induced ω phase transformation is accompanied with {3 3 2}β mechanical twinning. This resulted in the maintenance of acceptable ductility with relatively high strength. Among the examined alloys, the Ti-17Mo alloy shows the lowest Young's modulus and the largest increase in the Young's modulus. This alloy exhibits small springback and could be easily bent to the required shape during operation. Thus, Ti-17Mo alloy is considered to be a potential candidate for the spinal rods in spinal fixation devices.

Original languageEnglish
Pages (from-to)1990-1997
Number of pages8
JournalActa Biomaterialia
Issue number5
Publication statusPublished - 2012 May


  • Biomaterials
  • Changeable Young's modulus
  • Deformation-induced ω phase
  • Mechanical twinning
  • Springback

ASJC Scopus subject areas

  • Biotechnology
  • Biomaterials
  • Biochemistry
  • Biomedical Engineering
  • Molecular Biology


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