Stresses in alumina scales on high-temperature alloys measured by X-ray and optical methods

1997 ◽  
Vol 358 (1-2) ◽  
pp. 127-130 ◽  
Author(s):  
V. R. Vosberg ◽  
D. Clemens ◽  
M. G. Berger ◽  
W. J. Quadakkers ◽  
W. Fischer ◽  
...  
Keyword(s):  
High Temperature ◽  
Optical Methods ◽  
Alumina Scales ◽  
X Ray ◽  
High Temperature Alloys

X-ray determination of stresses in alumina scales on high temperature alloys

2000 ◽  
Vol 17 (1) ◽  
pp. 109-115 ◽  
Author(s):  
C. Sarioglu ◽  
E. Schumann ◽  
J. R. Blachere ◽  
F. S. Pettit ◽  
G. H. Meier
Keyword(s):  
High Temperature ◽  
Alumina Scales ◽  
X Ray ◽  
High Temperature Alloys

X-Ray Spectrographic Analysis of Nickel Containing Alloys with Varied Sample Forms

1957 ◽  
Vol 1 ◽  
pp. 351-366
Author(s):  
C. Manning Davis ◽  
George R. Clark
Keyword(s):  
High Temperature ◽  
Direct Analysis ◽  
Spectrographic Analysis ◽  
Internal Standards ◽  
X Ray ◽  
High Temperature Alloys

AbstractTechniques are presented whereby X-ray spectrographic analyses are carried out on alloys and metallurgical products which enter the Laboratory in the form of drillings, millings, or filings. The techniques described include direct analysis, with and without internal standards. Analysis of high temperature alloys without a aeries of chemically analysed standards by these techniques have greatly extended the usefulness of the X-ray spectrograph.

Thermal Alumina Scales on FeCrAl: Characterization and Growth Mechanism

2008 ◽  
Vol 595-598 ◽  
pp. 915-922 ◽  
Author(s):  
Sébastien Chevalier ◽  
Alain Galerie ◽  
Olivier Heintz ◽  
Remi Chassagnon ◽  
Alexandre Crisci
Keyword(s):  
Electron Microscope ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Growth Mechanism ◽  
Stable Phase ◽  
Alumina Scales ◽  
Temperature Oxidation ◽  
X Ray ◽  
Transient Phases ◽  
Alpha Alumina

High temperature oxidation resistance of alumina-forming materials is connected to the growth of dense, stable and protective alumina scales. Depending on temperature, impurities present in the base alloys, presence of water vapour in the oxidizing atmosphere, the alumina scales are composed of alpha-alumina (which is the stable phase obtained for temperatures over 1000°C) or of transient alumina (γ,θ,δ obtained for lower temperatures). It is generally considered that γ- Al2O3 grows when T<850°C, that θ-Al2O3 is present for 850°C<T<1000°C and that α-Al2O3 is stable when T exceeds 1000°C. The exact role played by transient alumina formation and/or transformation on the high temperature performances of alumina-forming materials is not exactly defined. Many works proposed that transient alumina phases grew during the first steps of the oxidation process and transformed into the stable phase after further oxidation. The transformation of transient phases in the stable alphaphase is generally accompanied by a volume contraction of around 14 %. In order to get better oxidation resistance, the formation of transient alumina is not wished, because: 1) their growth rate is generally higher than that of alpha-alumina with, as a consequence, a huge Al consumption, detrimental for the material resistance after long exposures, 2) the change in volume during the transformation of transient phases into alpha-alumina can generate stresses in the oxide scale and can weaken its adherence to the underlying substrate, leading to massive spallation. The present study deals with the coupling of different characterization tools in order to precisely identify the transient phases grown on FeCrAl materials. The use of scanning electron microscope (SEM-FEG), transmission electron microscope (TEM), Photoluminscescence Spectroscopy(PLS), X-ray photoelectron spectrometry (XPS) and X-ray diffraction at different glancing angles (XRD) on model materials oxidized at two temperatures (850 and 1100°C) could help the identification of transient phases. These techniques gave a better understanding of the alumina scale growth mechanism.

In Situ Measurement of Stresses in Alumina Scales by High Temperature X-Ray Diffraction

2001 ◽  
Vol 369-372 ◽  
pp. 547-554 ◽  
Author(s):  
Vladislav Kolarik ◽  
H. Fietzek ◽  
Maria Juez-Lorenzo ◽  
M. Gross
Keyword(s):  
High Temperature ◽  
In Situ Measurement ◽  
Alumina Scales ◽  
X Ray Diffraction ◽  
X Ray
Sign in / Sign up

Export Citation Format

Share Document