TY - JOUR
T1 - Heterogeneous grain refinement of biomedical Ti-29Nb-13Ta-4.6Zr alloy through high-pressure torsion
AU - Nakai, M.
AU - Niinomi, M.
AU - Hieda, J.
AU - Yilmazer, H.
AU - Todaka, Y.
N1 - Funding Information:
This work was supported in part by the Global COE Program “Materials Integration (International Center of Education and Research), Tohoku University”, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan , the Inter-University Cooperative Research Program “Highly-Functional Interface Science: Innovation of Biomaterials with Highly Functional Interface to Host and Parasite, Tohoku University and Kyushu University”, MEXT, Japan, Grants-in-Aid for Young Scientists (B), the Japan Society for the Promotion of Science (JSPS), Japan, Research Seeds Quest Program, Japan Science and Technology Agency (JST), Japan , the Cooperative Research Program of the Institute for Materials Research, Tohoku University, Japan , and the Cooperative Research Program of the Advanced Research Center of Metallic Glasses, Institute for Materials Research, Tohoku University, Japan.
Funding Information:
Hakan Yilmazer received B.S. and M.S degrees from the Department of Metallurgical and Materials Engineering at Istanbul Technical University, Turkey, in 2006 and 2008, respectively. He started as a research assistant in the Department of Materials Science at Tohoku University, supported by the program of Global Certificate of Excellence (GCOE) of the Japanese Government. He was admitted as a doctoral student at the Niinomi Laboratory in the Graduate School of Engineering at Tohoku University, Japan, in 2008. His research interests include: biomaterials, titanium based biomaterials, severe plastic deformation, nanostructuring, and nitriding.
PY - 2013/6
Y1 - 2013/6
N2 - The biomedical β-type titanium alloy Ti-29Nb-13Ta-4.6Zr (TNTZ) exhibits non-toxicity and a low Young's modulus that is similar to that of bone. This alloy has a low Young's modulus because it contains a metastable β phase. Strengthening due to grain refinement tends to provide high mechanical strength, while keeping the Young's modulus low, because it maintains the original β phase. In this case, severe plastic deformation, such as High-Pressure Torsion (HPT), is a potential treatment for obtaining these properties simultaneously. Thus, in this study, the effect of HPT on the microstructure and hardness of TNTZ was systematically investigated. On the cross sections of TNTZ subjected to HPT, heterogeneous microstructures, consisting of a matrix and an unetched band not corroded by an etching solution, were observed. Both the matrix and the unetched band were comprised of a single β phase with submicronsized grains, but their grain geometries differed: equiaxed grains and elongated grains are observed in the matrix and the unetched band, respectively. The hardness distribution in the cross section of TNTZ subjected to HPT is also heterogeneous; the hardness is higher in the matrix than in the unetched band, when the number of HPT rotations is small.
AB - The biomedical β-type titanium alloy Ti-29Nb-13Ta-4.6Zr (TNTZ) exhibits non-toxicity and a low Young's modulus that is similar to that of bone. This alloy has a low Young's modulus because it contains a metastable β phase. Strengthening due to grain refinement tends to provide high mechanical strength, while keeping the Young's modulus low, because it maintains the original β phase. In this case, severe plastic deformation, such as High-Pressure Torsion (HPT), is a potential treatment for obtaining these properties simultaneously. Thus, in this study, the effect of HPT on the microstructure and hardness of TNTZ was systematically investigated. On the cross sections of TNTZ subjected to HPT, heterogeneous microstructures, consisting of a matrix and an unetched band not corroded by an etching solution, were observed. Both the matrix and the unetched band were comprised of a single β phase with submicronsized grains, but their grain geometries differed: equiaxed grains and elongated grains are observed in the matrix and the unetched band, respectively. The hardness distribution in the cross section of TNTZ subjected to HPT is also heterogeneous; the hardness is higher in the matrix than in the unetched band, when the number of HPT rotations is small.
KW - Biomaterial
KW - Grain refinement
KW - Severe plastic deformation
KW - β-type titanium alloy
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U2 - 10.1016/j.scient.2013.01.004
DO - 10.1016/j.scient.2013.01.004
M3 - Article
AN - SCOPUS:84888346018
VL - 20
SP - 1067
EP - 1070
JO - Scientia Iranica
JF - Scientia Iranica
SN - 1026-3098
IS - 3
ER -