A Biomedical Ti-35Nb-5Ta-7Zr Alloy Fabricated by Powder Metallurgy
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JMEPEG (2019) 28:5616–5624 https://doi.org/10.1007/s11665-019-04294-7
A Biomedical Ti-35Nb-5Ta-7Zr Alloy Fabricated by Powder Metallurgy B.Q. Li and X. Lu (Submitted March 26, 2019; in revised form July 26, 2019; published online September 4, 2019) Ti-35Nb-5Ta-7Zr alloy for biomedical applications with a reduced YoungÕs modulus of less than 10 GPa, being comparable to that of human bones, was successfully fabricated by powder metallurgy method. The microstructure, compressive and tensile behavior were studied. Results indicate that Ti-rich and Ta-rich phases co-exist in b-matrix. Ti-35Nb-5Ta-7Zr alloys yield at about 10% in compression, with increasing in the content of process control agent, the resultant compressive yield strength and YoungÕs modulus increase from 650 ± 46 to 1055 ± 90 MPa and from 6.3 ± 0.03 to 8.24 ± 0.04 GPa, respectively. The tensile fractography of alloy with 9.7 GPa tensile YoungÕs modulus, 433 MPa UTS at the 5.5% elongation consists of cleavage fracture and ductile fracture with dimples. The failure mechanism has been discussed taking the intrinsic microstructural features into consideration. Keywords
mechanical properties, micropore structure, powder metallurgy, Ti-35Nb-5Ta-7Zr alloys
1. Introduction Ti alloys with wonderful mechanical properties, excellent biocompatibility and high corrosion resistance, such as Ti-6Al4V, Ti-48Al-2Cr-2Nb, Ti-48Al-2Cr-2Fe and TiNi, have been extensively used in biomedical applications (Ref 1-3). However, the release of metal ions from these metallic implant materials, e.g., Al, Ni, Fe, V and Co, can cause adverse biological effects or elicit allergy reactions (Ref 4). Investigations have demonstrated that Ti, Nb, Ta and Zr are favorable non-toxic metals with good biocompatibility (Ref 5-7). Based on the first principles theoretical investigations of b-Ti alloys, the addition of Nb, Ta and Zr in Ti alloys increase the stability of the b-phase, thus lowering the YoungÕs modulus (Ref 8-10). Therefore, Ti-Nb-Ta-Zr alloys are also known as attractive metallic biomaterials owing to their improved mechanical properties, comparable elastic modulus and excellent bioactivity (Ref 11-16). The preparation method of Ti and its alloys includes coldcrucible (Ref 17), rapid prototyping (Ref 18), casting (Ref 1921) and metallurgy (Ref 22). Acharya et al. (Ref 6) investigated the influence of Zr on the overall mechanical (yield strength of 766-876 MPa and modulus of 67 ± 3 GPa) and functional responses of a Ti-Nb-Ta-Zr-O alloy by casting. Ti-Nb-Zr shapememory alloys for medical implants experienced cold rolling and post-deformation annealing. The YoungÕs modulus showed B.Q. Li, Department of Mechanical Engineering, Jinzhong University, Jinzhong 030619, China; and Liaoning Key Materials Laboratory for Railway, Department of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028, China; X. Lu, Liaoning Key Materials Laboratory for Railway, Department of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028, China. Contact e-mails:
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