Influence of annealing on microstructure and mechanical properties of ultrafine-grained Ti45Nb

Bernhard Völker, Verena Maier-Kiener, Katharina Werbach, Timo Müller, Stefan Pilz, Mariana Calin, Jürgen Eckert, Anton Hohenwarter

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung

9 Zitate (Scopus)


Beta-Ti alloys have been intensively investigated in the last years because of their favorable low Young's moduli, biocompatibility and bio-inertness, making these alloys interesting candidates for implant materials. Due to their low mechanical strength, efforts are currently devoted to increasing it. A promising way to improve the strength is to tailor the microstructure using severe plastic deformation (SPD). In this investigation high pressure torsion was used to refine the microstructure of a Ti-45wt.%Nb alloy inducing a grain size of ~50 nm. The main focus of the subsequent investigations was devoted to the thermal stability of the microstructure. Isochronal heat-treatments performed for 30 min in a temperature range up to 500 °C caused an increase of hardness with a peak value at 300 °C before the hardness decreased at higher temperatures. Simultaneously, a distinct temperature-dependent variation of the Young's modulus was also measured. Tensile tests revealed an increase in strength after annealing compared to the SPD-state. Microstructural investigations showed that annealing causes the formation of α-Ti. The findings suggest that the combination of severe plastic deformation with subsequent heat treatment provides a feasible way to improve the mechanical properties of SPD-deformed β-Ti alloys making them suitable for higher strength applications.

FachzeitschriftMaterials and Design
Ausgabenummer5 October
PublikationsstatusVeröffentlicht - 5 Okt. 2019

Bibliographische Notiz

Funding Information:
This work was supported by the Austrian Science Fund FWF in the framework of Research Project P26729-N19 . This project was also partly funded by the European Research Council under ERC Grant Agreement No. 340185 USMS . Additional support through the German Research Foundation ( SFB/TRR 79 , project M1) and the European Research Council under the ERC Advanced Grant INTELHYB ( ERC-2013-ADG-340025 ) is gratefully acknowledged. Financial support by the Austrian Federal Government ( 837900 ) within the framework of the COMET Funding Programme (MPPE, project, A7.19) is also appreciated. The authors thank also G. Felber and S. Modritsch for their help with TEM and SEM sample preparation.

Publisher Copyright:
© 2019 The Authors

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