Microstructure Influence on Residual Stresses in Growing Chromia Oxide Films as Determined by In Situ High Temperature Raman Spectroscopy

Abstract:

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In this work, growth stresses have been investigated in relation with the microstructure in the case of α-Cr2O3 growing oxide films on NiCr30 alloy. The equibiaxial growth stresses have been measured thanks to a technique coupling Raman spectroscopy and in situ high temperature oxidation of the NiCr30 alloy in the temperature range [700°C-900°C]. The low acquisition time necessary to obtain a Raman spectrum allows to follow the chromia growth kinetic with sufficient accuracy. It is demonstrated that the growth stress in such oxide films can attain more than 2 GPa, before additional thermal stress arises on cooling. Moreover, the growth stress kinetic - subsequent establishment and relaxation - are highly microstructure sensitive: in particular, as the oxidation temperature rises, the chromia grain size also increases, and it consequently retards the occurrence of the creep relaxation phenomena which needs an additional stress to start.

Info:

Periodical:

Materials Science Forum (Volumes 595-598)

Edited by:

Pierre Steinmetz, Ian G. Wright, Alain Galerie, Daniel Monceau and Stéphane Mathieu

Pages:

881-888

DOI:

10.4028/www.scientific.net/MSF.595-598.881

Citation:

M. Kemdehoundja et al., "Microstructure Influence on Residual Stresses in Growing Chromia Oxide Films as Determined by In Situ High Temperature Raman Spectroscopy", Materials Science Forum, Vols. 595-598, pp. 881-888, 2008

Online since:

September 2008

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$35.00

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