Tohoku University. Research Profiles


Novel CoCr-based superelastic metallic biomaterial with low Young's modulus



General metallic biomaterials, such as stainless steels and conventional CoCr alloys, show a high Young's modulus ten times higher than that of human bones. This is an unfavored feature because it causes the so-called "stress shielding effect" when they are used as implants. β-type Ti alloys have a relatively lower Young's modulus, but they come with a compromise of low wear resistance. The current novel CoCr-based alloys are a breakthrough; they exhibit both a low Young's modulus similar to human bones and a high wear and corrosion resistance. Moreover, they exhibit superelasticity with a huge recoverable strain over 17%, also showing promise as shape memory alloys.

Targeted Application(s)/Industry

It is the first time that a low Young's modulus, a high corrosion and wear resistance, and a superior superelastic behavior are simultaneously obtained in a single material. The current novel CoCr-based alloys are promising for biomedical applications such as total hip or knee joint replacements, bone plates, spinal fixation devices, and vascular stents.


Department of Materials Science, Graduate School of Engineering

XU Xiao , Assistant Professor


Related Information

Takumi Odaira, Sheng Xu, Kenji Hirata, Xiao Xu,* Toshihiro Omori, Kosuke Ueki, Kyosuke Ueda, Takayuki Narushima, Makoto Nagasako, Stefanus Harjo,
Takuro Kawasaki, Lucie Bodnárová, Petr Sedlák, Hanuš Seiner, and Ryosuke Kainuma, Flexible and Tough Superelastic Co-Cr Alloys for Biomedical Applications, Advanced Materials, 34(27) (2022) 2202305.