Bending springback behavior related to deformation-induced phase transformations in Ti–12Cr and Ti–29Nb–13Ta–4.6Zr alloys for spinal fixation applications

• For Ti–12Cr, ω forms in both compression and tension areas during bending.
• For TNTZ, α″ forms in tension area and ω forms in compression area during bending.
• Ti–12Cr exhibits a smaller springback and greater bending strength than TNTZ.
• Ti–12Cr is considered a more desirable material for spinal fixation applications.

The springback behavior of Ti–12Cr and Ti–29Nb–13Ta–4.6Zr (TNTZ) during deformation by bending was investigated; and the microstructures of the non-deformed and deformed parts of both alloys were systematically examined to clarify the relationship between microstructure and springback behavior.For the deformed Ti–12Cr alloy, deformation-induced ω-phase transformation occurs in both the areas of compression and tension within the deformed part, which increases the Young׳s modulus. With the deformed TNTZ alloy, deformation-induced ω-phase transformation is observed in the area of compression within the deformed part; while a deformation-induced α″ martensite transformation occurs in the area under tension, which is likely to be associated with the pseudoelasticity of TNTZ. Among these two alloys, Ti–12Cr exhibits a smaller springback and a much greater bending strength when compared with TNTZ; making Ti–12Cr the more advantageous for spinal fixation applications.

Compared with TNTZ, Ti–12Cr exhibits a greater bending strength and a smaller springback which is owing to the different deformation products. Given that a combination of low springback and high strength is essential for practical use, Ti–12Cr is considered as the more desirable material for spinal fixation applications.Figure optionsDownload high-quality image (203 K)Download as PowerPoint slide