Mechanical and microstructural characterization of new nickel-free low modulus β-type titanium wires during thermomechanical treatments

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:636

Article

Guillem-Marti, J.^1,2,3  Herranz-Diez, C.^1,2  Shaffer, J. E.⁴  Gil, F. J.^1,2,3  Manero, J. M.^1,2,3 

[1] Tech Univ Catalonia UPC, ETSEIB, Dept Mat Sci & Met, Biomat Biomech & Tissue Engn Grp, Barcelona 08028, Spain

[2] Biomed Res Networking Ctr Bioengn Biomat & Nanome, Zaragoza 50018, Spain

[3] Ctr Res NanoEngn CRNE UPC, Barcelona 08028, Spain

[4] Ft Wayne Met Res Prod Corp, Ft Wayne, IN 46809 USA

关键词: Nickel-free titanium alloys;    Pseudo-elasticity;    Low elastic modulus;    Wires;    Large plastic deformation;   

DOI  :  10.1016/j.msea.2015.03.060

来源: Elsevier

【 摘 要 】

NiTi alloy is the only practical shape memory alloy (SMA) in biomedical use because of its excellent mechanical stability and functionality. However, it is estimated that between 4.5% and 28.5% of the population are hypersensitive to nickel metal, with a higher prevalence in females. Therefore, developing nickel-free low modulus beta-type titanium alloys showing shape memory or super elastic behavior would have a great interest in the biomaterials field. Homogeneous 127 mu m diameter Ti25Hf21Nb wires were produced and compared to straight annealed Ti-50.8 at% Ni (Nitinol) and 90% cold-drawn 316L wires. Microstructural changes taking place during the heat treatment of cold-worked Ti25Hf21Nb wires were investigated. Large plastic deformation during wire drawing and subsequent annealing led to nano-crystallization and amorphization which may contribute to the observed superelasticity. Mechanical properties were characterized using cyclic uniaxial tension and rotary beam fatigue test modes. A modulus of elasticity of less than 60 GPa and axial recoverable strain of greater than 3% were observed with stress hysteresis resembling a reversible stress-induced martensitic transformation at higher temperatures. The new Ti25Hf21Nb alloy is an important candidate for developing Ni-free SMAs in the future. (C) 2015 Elsevier B.V. All rights reserved.

【 授权许可】

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