Low-Modulus Ti Alloys Suitable for Rods in Spinal Fixation Devices

Abstract

Low-Young's modulus Ti alloys are expected to be suitable for use in the rods of spinal fixation devices. However, in addition to a low Young's modulus, the rods must also exhibit a high Young's modulus at the deformed region to reduce springback when surgeons bend the rod inside the narrow bodies of patients. Ti-Mo and Ti-Cr alloys are potential candidates to satisfy these two conflicting demands. In these alloys, known as Young's modulus changeable or Young's modulus selfadjustable Ti alloys, the ω-phase with high Young's modulus is induced by deformation. Among these alloys, Ti-12Cr is judged to be the most suitable for use in the rods of spinal fixation devices. This alloy exhibits a high uniaxial fatigue strength, and its compressive fatigue strength is significantly improved by cavitation peening.

Eutectic composition titanium metal matrix composites for laser powder bed fusion via surface remelt analyses

“…the microstructure is β -Ti (lm m [229]) + cubic TiFe. Reflections associated with orthorhombic martensite and ω phases are notably absent in the laser remelt diffraction pattern [41, 42].…”

Preliminary study on the phase transformation of Ti-3Mo applying solid solution treatment for bone implant application

“…αβphase and β -phase titanium is widely used as biomaterials [11]. The presence of β -phase titanium gives better biocompatibility when compared to the α -phase titanium only, because the value of Young's modulus is almost the same as that of cortical bone has, so it can minimize stress shielding phenomenon [14]. Stress shielding is an inappropriate load transfer phenomenon from artificial bone implants to the real bone [15].…”

“…Molybdenum is considered to be an alternative β -phase stabilizer due to nontoxic and nonallergenic for the human body [14]. Molybdenum is an element that has a lower harmful effect (toxicity level) compared to any other elements, such as Co, Ni, and Cr.…”

Effects of shot-peening and atmospheric-pressure plasma on aesthetic improvement of Ti–Nb–Ta–Zr alloy for dental applications

“…It has excellent chemical, physical, and mechanical properties, such as corrosion resistance, antitoxicity, biocompatibility, and a minimum Young's modulus of approximately 60 GPa, and it can significantly promote the development of biomedical devices for hard tissue reconstruction, such as bone implants or spinal fixation devices. [2][3][4] Also, its excellent properties will be suitable for dental devices such as orthodontic wires or dental implants as well.…”