Creep-life prediction of service-exposed turbine blades

We study the possibility of prediction of the service life of gas-turbine blades made of nickel alloys according to the results of accelerated testing of specimens cut out from these blades. The predictions are carried out with the help of two methods: by using the Larson-Miller parameter and according to Robinson's rule. It is shown that the predictions performed by using the Larson-Miller parameter on the basis of extrapolation of the data of accelerated tests are possible but give underestimated results for the durations of service life greater than 80,000 h, which is explained by the changes in the microstructure of the material in the course of long-term operation of the blades.