Impacts of trace carbon on the microstructure of as-sintered biomedical Ti-15Mo alloy and reassessment of the maximum carbon limit

M Yan; M Qian; C Kong; M S Dargusch

doi:10.1016/j.actbio.2013.10.034

Impacts of trace carbon on the microstructure of as-sintered biomedical Ti-15Mo alloy and reassessment of the maximum carbon limit

Acta Biomater. 2014 Feb;10(2):1014-23. doi: 10.1016/j.actbio.2013.10.034. Epub 2013 Nov 4.

Authors

M Yan¹, M Qian², C Kong³, M S Dargusch⁴

Affiliations

¹ The University of Queensland, Queensland Centre for Advanced Materials Processing and Manufacturing (AMPAM), School of Mechanical and Mining Engineering, Brisbane, Qld 4072, Australia; The University of Queensland, School of Mechanical and Mining Engineering, ARC Centre of Excellence for Design in Light Metals, Brisbane, Qld 4072, Australia.
² The University of Queensland, School of Mechanical and Mining Engineering, ARC Centre of Excellence for Design in Light Metals, Brisbane, Qld 4072, Australia. Electronic address: ma.qian@uq.edu.au.
³ Electron Microscopy Unit, University of New South Wales, Sydney, NSW 2052, Australia.
⁴ The University of Queensland, Queensland Centre for Advanced Materials Processing and Manufacturing (AMPAM), School of Mechanical and Mining Engineering, Brisbane, Qld 4072, Australia. Electronic address: m.dargusch@uq.edu.au.

PMID: 24200712
DOI: 10.1016/j.actbio.2013.10.034

Abstract

The formation of grain boundary (GB) brittle carbides with a complex three-dimensional (3-D) morphology can be detrimental to both the fatigue properties and corrosion resistance of a biomedical titanium alloy. A detailed microscopic study has been performed on an as-sintered biomedical Ti-15Mo (in wt.%) alloy containing 0.032 wt.% C. A noticeable presence of a carbon-enriched phase has been observed along the GB, although the carbon content is well below the maximum carbon limit of 0.1 wt.% specified by ASTM Standard F2066. Transmission electron microscopy (TEM) identified that the carbon-enriched phase is face-centred cubic Ti2C. 3-D tomography reconstruction revealed that the Ti2C structure has morphology similar to primary α-Ti. Nanoindentation confirmed the high hardness and high Young's modulus of the GB Ti2C phase. To avoid GB carbide formation in Ti-15Mo, the carbon content should be limited to 0.006 wt.% by Thermo-Calc predictions. Similar analyses and characterization of the carbide formation in biomedical unalloyed Ti, Ti-6Al-4V and Ti-16Nb have also been performed.

Keywords: 3-D tomography; Biomedical titanium alloys; Carbon limit; Titanium carbides.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Alloys / chemistry*
Carbon / analysis*
Imaging, Three-Dimensional
Mechanical Phenomena
Microscopy, Electron, Scanning
Phase Transition

Substances

Alloys
titanium molybdenum alloy
Carbon