Thermal stability and latent heat of Nb–rich martensitic Ti-Nb alloys

Author(s)
Matthias Bönisch, Ajit Panigrahi, Mariana Calin, Thomas Waitz, Michael Zehetbauer, Werner Skrotzki, Jürgen Eckert
Abstract

Ti-Nb-based alloys are candidate materials for load-bearing and for functional biomedical implant components. For these applications alloy compositions with relatively low martensitic transformation (MT) temperatures are of highest interest. In this work we examine the thermal stability and the temperature-induced β ↔ α″ MT of Nb-rich martensitic and partially martensitic Ti-Nb alloys exhibiting martensite start temperatures Ms < 300°C. The first part of this article investigates the phase transformations and precipitation reactions occurring during isochronal cycling in dependence of the Nb content using differential scanning calorimetry and dilatometry in combination with X-ray diffraction. The second part studies the temperatures, thermal hysteresis and transformation interval of the β ↔ α″ MT. The latent heat, elastic and irreversible energy contributions of the thermoelastic energy balance are quantified in dependence of Nb content in the remaining parts. All energy contributions decrease with increasing Nb content and the latent heat becomes very small (< 5 J/g) for the Nb-richest martensitic compositions. Above a critical Nb concentration the β → α″ MT is incomplete.

Organisation(s)
Physics of Nanostructured Materials
Journal
Journal of Alloys and Compounds
Volume
697
Pages
300-309
No. of pages
10
ISSN
0925-8388
DOI
https://doi.org/10.1016/j.jallcom.2016.12.108
Publication date
03-2017
Publication status
Published
Peer reviewed
Yes
Austrian Fields of Science 2012
103018 Materials physics
Keywords
Differential scanning calorimetry, Dilatometry, Hysteresis, Omega-phase, Precipitation
ASJC Scopus subject areas
Mechanics of Materials, Mechanical Engineering, Metals and Alloys, Materials Chemistry
Portal url
https://ucris.univie.ac.at/portal/en/publications/thermal-stability-and-latent-heat-of-nbrich-martensitic-tinb-alloys(1979917d-a7df-45ce-bead-52c59bdf3738).html