22509.pdf (1.52 MB)

Microstructural and chemical rejuvenation of a Ni-based superalloy

Download (1.52 MB)
journal contribution
posted on 20.09.2016 by Zhiqi Yao, C.C. Degnan, Mark Jepson, Rachel Thomson
The microstructural evolution of the Ni-based superalloy CMSX-4 including the change in gamma prime morphology, size and distribution after high temperature degradation and subsequent rejuvenation heat treatments has been examined using field emission gun scanning electron microscopy (FEGSEM) and transmission electron microscopy (TEM). In this paper it is shown that there are significant differences in the size of the ‘channels’ between gamma prime particles, the degree of rafting and the size of tertiary gamma prime particles in each of the different microstructural conditions studied. Chemical analysis has been carried out to compare rejuvenated and pre-service samples after the same subsequent degradation procedure. The results indicate that although the microstructure of pre-service and rejuvenated samples are similar, chemical differences are more pronounced in the rejuvenated samples, suggesting that chemical segregation from partitioning of the elements was not completely eliminated through the applied rejuvenation heat treatment. A number of modified rejuvenation heat treatment trials were carried out to reduce the chemical segregation prior to creep testing. The creep test results suggest that chemical segregation has an immeasurable influence on the short-term mechanical properties under the test conditions used here, indicating that further work is required to fully understand the suitability of specific rejuvenation heat treatments and their role in the extension of component life in power plant applications.



  • Aeronautical, Automotive, Chemical and Materials Engineering


  • Materials

Published in

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science


YAO, Z. ... et al., Microstructural and chemical rejuvenation of a Ni-based superalloy. Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, 47 (12), pp.6330-6338.


Springer Verlag (Germany)/ © The authors


VoR (Version of Record)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/

Acceptance date


Publication date



This is an open access article published by Springer and distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), http://creativecommons.org/licenses/by/4.0/