Giant thermal expansion and α-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 (+ 163.9×10

-6 to-95.1×10

-6 °C

-1) ever reported. Moreover, we describe two pathways leading to the precipitation of the α-phase mediated by diffusion-based orthorhombic structures, α″

lean and α″

iso. Via coupling the lattice parameters to composition both phases evolve into α through rejection of Nb. These findings have the potential to promote new microstructural design approaches for Ti-Nb alloys and β-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
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
ASJC Scopus subject areas
General Physics and Astronomy, General Chemistry, General Biochemistry,Genetics and Molecular Biology
Portal url
https://ucrisportal.univie.ac.at/en/publications/78c98f1b-79cb-488b-a01f-d88c8e16a27c