Giant thermal expansion and alpha-precipitation pathways in Ti-alloys

Author(s)
Matthias Boenisch, Ajit Panigrahi, Mihai Stoica, Mariana Calin, Eike Ahrens, Michael Zehetbauer, Werner Skrotzki, Juergen Eckert
Abstract

Ti-alloys represent the principal structural materials in both aerospace development and metallic biomaterials. Key to optimizing their mechanical and functional behaviour is in-depth know-how of their phases and the complex interplay of diffusive vs. displacive phase transformations to permit the tailoring of intricate microstructures across a wide spectrum of configurations. Here, we report on structural changes and phase transformations of Ti-Nb alloys during heating by in situ synchrotron diffraction. These materials exhibit anisotropic thermal expansion yielding some of the largest linear expansion coefficients (+ 163.9 x 10(-6) to -95.1 x 10(-6) degrees C-1) ever reported. Moreover, we describe two pathways leading to the precipitation of the alpha-phase mediated by diffusion-based orthorhombic structures, alpha ''(lean) and alpha ''(iso). Via coupling the lattice parameters to composition both phases evolve into a through rejection of Nb. These findings have the potential to promote new microstructural design approaches for Ti-Nb alloys and beta-stabilized Ti-alloys in general.

Organisation(s)
Physics of Nanostructured Materials
External organisation(s)
Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, Technische Universität Dresden, Montanuniversität Leoben, Österreichische Akademie der Wissenschaften (ÖAW), Institute of Minerals and Materials Technology, Bhubaneswar
Journal
Nature Communications
Volume
8
No. of pages
9
ISSN
2041-1723
DOI
https://doi.org/10.1038/s41467-017-01578-1
Publication date
11-2017
Peer reviewed
Yes
Austrian Fields of Science 2012
103018 Materials physics
Keywords
Portal url
https://ucris.univie.ac.at/portal/en/publications/giant-thermal-expansion-and-alphaprecipitation-pathways-in-tialloys(78c98f1b-79cb-488b-a01f-d88c8e16a27c).html