Journal Article

PUBDB-2015-02088

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png High Temperature Oxidation Resistance in Titanium–Niobium Alloys

Tegner, B. E. ; Zhu, L. ; Siemers, C.>Extern* ; Saksl, K. ; Ackland, G. J. (Corresponding Author)

2015
Elsevier Lausanne

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Please use a persistent id in citations: doi:10.1016/j.jallcom.2015.04.115

Abstract: Titanium alloys are ideally suited for use as lightweight structural materials, but their use at high temperature is severely restricted by oxidation. Niobium is known to confer oxidation-resistance, and here we disprove the normal explanation, that Nb5+ ions trap oxygen vacancies. Using density functional theory calculation, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) we show that Nb is insoluble in TiO2. In fact, the Ti–Nb surface has three-layer structure: the oxide itself, an additional Nb-depleted zone below the oxide and a deeper sublayer of enhanced Nb. Microfocussed X-ray diffraction also demonstrates recrystallization in the Nb-depleted zone. We interpret this using a dynamical model: slow Nb-diffusion leads to the build up of a Nb-rich sublayer, which in turn blocks oxygen diffusion. Nb effects contrast with vanadium, where faster diffusion prevents the build up of equivalent structures.

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Contributing Institute(s):

1. DOOR-User (DOOR)

Research Program(s):

1. 6G3 - PETRA III (POF3-622) (POF3-622)

Experiment(s):

1. DORIS Beamline BW5 (DORIS III)
2. PETRA Beamline P07 (PETRA III)

Appears in the scientific report 2015

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Database coverage:
; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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