title: Mechanical properties, structural and texture evolution of biocompatible Ti-45Nb alloy processed by severe plastic deformation.
abstract: Biocompatible β Ti-45Nb (wt%) alloys were subjected to different methods of severe plastic deformation (SPD) in order to increase the mechanical strength without increasing the low Young׳s modulus thus avoiding the stress shielding effect. The mechanical properties, microstructural changes and texture evolution were investigated, by means of tensile, microhardness and nanoindentation tests, as well as TEM and XRD. Significant increases of hardness and ultimate tensile strength up to a factor 1.6 and 2, respectively, could be achieved depending on the SPD method applied (hydrostatic extrusion - HE, high pressure torsion - HPT, and rolling and folding - R&F), while maintaining the considerable ductility. Due to the high content of β-stabilizing Nb, the initial lattice structure turned out to be stable upon all of the SPD methods applied. This explains why with all SPD methods the apparent Young׳s modulus measured by nanoindentation did not exceed that of the non-processed material. For its variations below that level, they could be quantitatively related to changes in the SPD-induced texture, by means of calculations of the Young׳s modulus on basis of the texture data which were carefully measured for all different SPD techniques and strains. This is especially true for the significant decrease of Young׳s modulus for increasing R&F processing which is thus identified as a texture effect. Considering the mechanical biocompatibility (percentage of hardness over Young׳s modulus), a value of 3-4% is achieved with all the SPD routes applied which recommends them for enhancing β Ti-alloys for biomedical applications.
authors.affiliation: Physics of Nanostructured Materials, Faculty of Physics, University of Vienna, 1090 Vienna, Austria. Electronic address: ajit.panigrahi@univie.ac.at.
authors.forename: Ajit
authors.initials: A
authors.lastname: Panigrahi
authors.affiliation: Physics of Nanostructured Materials, Faculty of Physics, University of Vienna, 1090 Vienna, Austria; Department of Material Science and Non-Ferrous Metals Engineering, Faculty of Non-Ferrous Metals, AGH-University of Science and Technology, 30-059 Kraków, Poland.
authors.forename: Bartosz
authors.initials: B
authors.lastname: Sulkowski
authors.affiliation: Physics of Nanostructured Materials, Faculty of Physics, University of Vienna, 1090 Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Waitz
authors.affiliation: Faculty of Materials Science and Engineering, Warsaw University of Technology, Woloska 141, 02-507 Warsaw, Poland.
authors.forename: Kadir
authors.initials: K
authors.lastname: Ozaltin
authors.affiliation: Faculty of Materials Science and Engineering, Warsaw University of Technology, Woloska 141, 02-507 Warsaw, Poland.
authors.forename: Witold
authors.initials: W
authors.lastname: Chrominski
authors.affiliation: Institute of Structural Physics, Dresden University of Technology, D-01062 Dresden, Germany.
authors.forename: Aurimas
authors.initials: A
authors.lastname: Pukenas
authors.affiliation: Physics of Nanostructured Materials, Faculty of Physics, University of Vienna, 1090 Vienna, Austria; Health & Environment Department, AIT Austrian Institute of Technology GmbH, Biomedical Systems, 2700 Wr. Neustadt, Austria.
authors.forename: Jelena
authors.initials: J
authors.lastname: Horky
authors.affiliation: Faculty of Materials Science and Engineering, Warsaw University of Technology, Woloska 141, 02-507 Warsaw, Poland.
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Lewandowska
authors.affiliation: Institute of Structural Physics, Dresden University of Technology, D-01062 Dresden, Germany.
authors.forename: Werner
authors.initials: W
authors.lastname: Skrotzki
authors.affiliation: Physics of Nanostructured Materials, Faculty of Physics, University of Vienna, 1090 Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Zehetbauer
mesh_terms: D000497:Alloys / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry*; D055119:Elastic Modulus; D008422:Materials Testing; D009556:Niobium; D013718:Tensile Strength; D014025:Titanium
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D009556:Niobium; D014025:Titanium
keywords: Mechanical properties; Severe plastic deformation; Texture evolution; Young׳s modulus; β-titanium alloy