Establishment of basic characteristics of martensitic transformation in Zr alloys and development of novel biomedical shape memory alloys

2018 Fiscal Year Final Research Report

• Project/Area Number: 16H04514
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Structural/Functional materials
• Research Institution: University of Tsukuba
• Principal Investigator: KIM HEE YOUNG 筑波大学, 数理物質系, 教授 (20333841)
• Research Collaborator: MIYAZAKI Shuichi
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: マルテンサイト変態 / 形状記憶合金 / 超弾性合金 / ジルコニウム合金 / 集合組織 / 力学特性 / 生体材料

Outline of Final Research Achievements

In order to develop biomedical shape memory and superelastic alloys with high biocompatibility and magnetic resonance imaging compatibility, novel Zr-Nb based alloys were designed, and the transformation characteristics and deformation behavior were investigated. It is clarified that the suppression of omega phase is important to exhibit superelasticity in Zr-Nb based alloys and the addition of Al and Sn is useful to suppress the formation of omega phase. The effects of Sn and Al on the crystal structure, microstructure, and mechanical properties of Zr-Nb alloys were systematically investigated and a composition range exhibiting shape memory effect and superelasticity was established. Zr-Nb-Al and Zr-Nb-Sn alloys are found to be promising candidates for novel biomedical alloys having low magnetic susceptibility, biocompatibility, shape memory effect and superelasticity.

Free Research Field

構造・機能材料

Academic Significance and Societal Importance of the Research Achievements

Zr-Nb-Al系およびZr-Nb-Sn系合金の結晶構造、微細組織、機械的特性に及ぼすAl、Sn、Nb濃度の影響を系統的に調査し、低磁化率および超弾性を示す新規Zr合金の開発に成功した。結晶学的理論を用いマルテンサイト変態の結晶学的パラメータを計算し、Zr合金におけるマルテンサイト変態の結晶学の確立に貢献した。Zr系合金での形状記憶効果および超弾性発現は世界初であり、MRIアーチファクトの少ない新たな生体用超弾性合金の開発に貢献する成果が得られた。医療用のデバイスやインプラント用の合金としての応用が期待できる。