ISSN:
1573-4889
Keywords:
Fe-base superalloy
;
oxidation
;
corrosion in water vapor
;
creep rupture strength in water vapor
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The oxidation kinetics and creep behavior of Incoloy 800 were studied in air and in water vapor charged with oxygen. Oxidation kinetics were determined by thermogravimetry. The creep behavior of samples tested in air and in H2O∶O2=1∶1 atmospheres was investigated by electron microscopic techniques. The oxidation rate of samples tested in air was governed by a p-conducting chromia interlayer. Depending upon water vapor pressure, chromia became n-conductive. As a consequence, a continuous rate-governing silica interlayer formed. The oxygen activity in the alloy was established by the dissociative pressure of the respective diffusion-rate-governing oxide scale. The stability of the dispersion-hardening Ti(C, N) particulates within the alloy was affected by the respective oxygen activity. In the samples tested in air, partial oxidation of the particulates due to enhanced oxygen activity caused a loss of coherency with the matrix. As a result, the deformation behavior during creep was changed to planar-slip mode, bringing about loss of creep resistance and ductility.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00664803
