Untitled

Göbel, M.; Haanappel, V.A.C.; Stroosnijder, M.F.

doi:10.1023/a:1010333410938

Cited by 27 publications

(9 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Nevertheless, results obtained by measuring the ODZ of other Ti alloys confirm the linear relationship between oxygen content and hardness [17,18]. To correlate oxygen diffusion, microhardness and lattice parameters, data are available in the literature for other titanium alloys [18]. However, the originality of the present work lies in the data obtained for lattice parameters; oxygen concentration is proportional to the c/a lattice parameter, which is proportional to microhardness.…”

Section: Discussionsupporting

confidence: 54%

Section: Discussionmentioning

confidence: 72%

“…It is relatively complicated to determine precise oxygen content in the metal/oxide interface. Some studies have shown this oxygen content to be dependent on temperature and exposure time [3,18,22]. For a given temperature, stabilization of oxygen content is expected at the metal oxide interface.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Observation using synchrotron X-ray diffraction of the crystallographic evolution of α-titanium after oxygen diffusion

Baillieux

Poquillon

Malard

2015

Philosophical Magazine Letters

View full text Add to dashboard Cite

In this study, the effect of oxygen diffusion on the crystallographic evolution of α-titanium has been studied using synchrotron X-ray diffraction. Measurements were carried out directly on sample cross-sections that were directly pre-oxidized at high temperature. Changes in hardness, oxygen content and lattice parameters after oxidation were determined by coupling microhardness measurements and electron probe microanalyzer results. IntroductionTitanium and its alloys are widely used in a variety of applications, including the aerospace and chemical industries. This widespread use is because of titanium's mechanical properties, low density and good corrosion resistance. Presently, aerospace manufacturers try to reduce weight, while increasing engine efficiency, often by exposing different components made of Ti-base alloys to higher temperatures. The effect of oxidation on the mechanical properties must therefore be taken into account.The O-Ti (oxygen-titanium) system and the oxidation of titanium have been extensively studied, but few correlations between oxygen concentration and α-titanium crystallographic modifications exist [1,2]. At temperatures above 600-700°C, the oxidation rate is parabolic; it then becomes linear with increasing temperature. This oxidation leads to the formation of an oxide layer (OL) on the surface with an oxygen diffusion zone (ODZ) in the metal. In this temperature range, TiO 2 rutile, an n-type semiconductor, has been observed to form an OL on pure titanium during oxidation [1,3]. The oxide that is initially formed is compact, but after extended exposure, multiple OLs are observed and can be associated with oxide spallation [6]. Even during the parabolic stage, the oxidation mechanism of titanium is complex owing to the high solubility of oxygen in the hexagonal-close-packed (hcp) structure of α-titanium (up to 30 at.%). During oxidation, oxygen diffusion and dissolution under the OL lead to development of the ODZ. This solid solution is harder and more brittle than the initial metal [4,5]. The depth of the ODZ increases with increasing temperature and duration of exposure. Understanding the oxidation mechanism of titanium requires a study of both OL growth and dissolution, as well as diffusion of oxygen in titanium (ODZ growth).

show abstract

Section: Discussionsupporting

confidence: 54%

Section: Discussionmentioning

confidence: 72%

See 1 more Smart Citation

Observation using synchrotron X-ray diffraction of the crystallographic evolution of α-titanium after oxygen diffusion

Baillieux

Poquillon

Malard

2015

Philosophical Magazine Letters

View full text Add to dashboard Cite

show abstract

“…7 imply more than two-fold increase in hardness beneath the OL. Gradual decrease of hardness from surface to the core is closely related to oxygen concentration across the ODZ [25][26][27][28].…”

Section: Analysis Of Hardness Measurementsmentioning

confidence: 99%

“…(3) can be calculated from "ln HV X vs. X" graphs as presented in Table 1. It has been reported that "HV-X" profiles obtained through hardness measurements are successfully used to investigate the diffusion kinetics by assuming the correlation between the hardness and the concentration of the dissolved oxygen [3,[24][25][26][27].…”

Section: Analysis Of Hardness Measurementsmentioning

confidence: 99%

Oxidation of Ti–6Al–4V alloy

Güleryüz

Çi̇menoǧlu

2009

Journal of Alloys and Compounds

296

126

View full text Add to dashboard Cite

Electrochemical Metallization of Solid Terbium Oxide

et al. 2006

View full text Add to dashboard Cite

Heavy rare-earth (HRE) metals function very efficiently in advanced materials for magnetooptical-information storage, giant magnetostrictive energy conversion, and high-strength permanent magnets.[1] A 7 % annual growth in global demand for rare-earth (RE) metals was recently predicted. [2] Although the separation of mixed RE compounds has been greatly refined, [3] extraction of pure RE metals, especially the heavy ones, remains a historical challenge. The difficulty is multifold but particularly related to the high oxygen affinity of HRE metals. Current industrial methods convert HRE oxides into fluorides (e.g. by reaction with HF or NH 4 F), from which the metal is extracted by calciothermic reduction at % 1500 8C in argon.[4] The obtained HRE metal needs further separation from excess calcium under vacuum and deoxygenation by special methods.[5] HRE metals have high melting points (> 1350 8C), and hence cannot be extracted as a liquid in the same way as aluminum and light RE metals. [6] Electrodeposited solid reactive metals from molten salts are always dendritic and absorb oxygen easily when exposed to air. Dendrite formation may be avoided by deposition onto a suitable transition-metal substrate to form a liquid alloy, [7] but the alloy composition is difficult to control precisely.Recently, solid TiO 2 , [8] SiO 2 , [9] and some mixed oxides [10] were electrochemically reduced to the respective solid metals or alloys in molten salts. The new process requires that 1) the metal oxides to be reduced are thermodynamically less stable than the oxide of the metal element of the molten salt used, [8][9][10][11][12][13] and 2) electrodeposition of the metal of the molten salt should be avoided.[8] CaO is extremely stable, and hence molten CaCl 2 is the preferred choice for the new process. However, HRE oxides are almost as stable as CaO, and their reduction may not occur at potentials more positive than that[*] Dr.

show abstract

Untitled

Cited by 27 publications

References 18 publications

Observation using synchrotron X-ray diffraction of the crystallographic evolution of α-titanium after oxygen diffusion

Observation using synchrotron X-ray diffraction of the crystallographic evolution of α-titanium after oxygen diffusion

Oxidation of Ti–6Al–4V alloy

Electrochemical Metallization of Solid Terbium Oxide

Contact Info

Product

Resources

About