Phase decomposition in an Fe-40 at.% Cr alloy after isothermal aging and its effect on hardening
The phase decomposition process of an Fe-40 at.% Cr alloy was studied after isothermal aging at 475 and 500 deg. C using a high-resolution transmission electron microscope, as well as hardness measurements. High-resolution transmission electron microscope observations showed that the hardening behavior is associated with the formation of the nanometric coherent decomposed Cr-rich and Fe-rich phases with irregular shape and interconnected as expected for a spinodally-decomposed alloy. As the aging progressed, coherent rounded Cr-rich phase precipitates were observed in the Fe-rich phase matrix. The coarsening process of the Cr-rich phase was observed for aging times up to 750 h. Nevertheless, no decrease in hardness with time was observed because of the nanometric size of the Cr-rich phase, less than 10 nm. Aging hardening was higher at 500 deg. C because of the higher decomposition kinetics. - Research Highlights: {yields} Spinodally-decomposed phases showed an interconnected and irregular shape in aged Fe-Cr alloy. {yields} Further aging promoted the formation of nanometric coherent rounded Cr-rich precipitates. {yields} Nanometric Cr-rich phases are responsible for the age hardening. {yields} Coarsening process of these nanometric Cr-rich precipitates caused no decrease in hardness.
- OSTI ID:
- 22066381
- Journal Information:
- Materials Characterization, Vol. 62, Issue 8; Other Information: Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
- Country of Publication:
- United States
- Language:
- English
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