Elastic modulus softening phenomena caused by deformation-induced phase transformation in Ti alloys and its application to biomaterials

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K22059
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 26:Materials engineering and related fields
• Research Institution: Osaka City University (2021); Osaka University (2019-2020)
• Principal Investigator: Tane Masakazu 大阪市立大学, 大学院工学研究科, 教授 (80379099)
• Project Period (FY): 2019-06-28 – 2022-03-31
• Keywords: 塑性変形 / 相変態 / チタン合金 / 弾性論

Outline of Final Research Achievements

For Ti alloys whose stability of the bcc structure was lowered to reduce the elastic modulus, the plastic deformation mode depending on the stability of the bcc structure and the change in elastic modulus caused the deformation-induced omega transformation were clarified. Furthermore, a strategy for the evaluation of the change in elastic modulus with the plastic deformation and omega-phase formation, which combines an effective-mean field theory and Voigt-Reuss-Hill approximation, was constructed. This strategy is applicable to the design of biomedical implants.

Free Research Field

構造・機能材料

Academic Significance and Societal Importance of the Research Achievements

生体用インプラント材料として重要な低弾性率化を実現したbcc構造を有するTi合金・単結晶に対して、bcc構造の安定性に依存した変形モードによる塑性変形と変形誘起オメガ変態に伴う弾性率変化との相関関係を明らかにしたことが本研究の学術的意義である。さらに、塑性変形および変形誘起相転移に伴う弾性率変化を考慮して生体インプラント材料の設計が可能であることを示したことが社会的意義として挙げられる。