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Title:
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Mechanical and microstructural characterization of new nickel-free low modulus beta-type titanium wires during thermomechanical treatments
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Author:
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Guillem Martí, Jordi; Herranz-Diez, Carolina; Shaffer, J.E.; Gil Mur, Francisco Javier; Manero Planella, José María
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Notes:
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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 β-type titanium alloys showing shape memory or super elastic behavior would have a great interest in the biomaterials field. Homogeneous 127 μm 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. |
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Subject(s):
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-Aliatges de titani sense níquel
-Pseudoelasticitat
-Filferros de mòdul elàstic baix
-Gran deformació plàstica
-Aleaciones de titanio sin níquel
-Pseudoelasticity
-Alambre de módulo elástico bajo
-Gran deformación plástica
-Nickel-free titanium alloys
-Pseudoelasticity
-Low elastic modulus wires
-Great plastic deformation
-616.3 |
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Rights:
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© 2015 Elsevier B.V. All rights reserved.
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Document type:
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Article
Article - Accepted version |
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Published by:
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Elsevier
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Share:
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