Service Temperature Evaluation of Cast K465 Superalloy Turbine Vane Based on Microstructural Evolution

Abstract

The overtemperature in a vane made of cast K465 superalloy is investigated in this paper. The vane was taken from a K465 guide ring after the service for specific period of time. The relationship between the temperature and content of γ´ precipitates was established for the K465 superalloy, which was then used to make the microstructural evolution analysis on failed turbine vane associated with overtemperature. The content of γ´ precipitates in dendritic region and the volume fraction of melting zone in interdendritic region in K465 superalloy were used as the microstructural parameters to check the overtemperature. It is found that there is a sound relationship between the parameters and the temperature. On the basis of this relationship, the microstructural evolution along with temperature variation of the overtemperature K465 turbine vane can be analyzed and the overall service temperature which the K465 guide ring experienced can be evaluated.