EXAMINATION OF CHANGES IN MICROSTRUCTURE OF TURBINE VANES WITH THE USE OF NON-DESTRUCTIVE METHODS
The processes associated with operation of traction, marine and avionic turbine engines entail occurrence of various defects affecting turbine components, in particular turbine vanes. The main reasons for defects and deterioration of gas turbine vanes include thermal fatigue and overheating of the vane material. This is why continuous monitoring of technical condition demonstrated by crucial engine components, such as turbine vanes, is a matter of great importance. The monitoring operations
... ring operations involve all the up-to-date diagnostic methods intended to detect and interpret possible hazards. The initial assessment is carried out with the use of visual inspection methods, but the major phase of investigations consists in metallographic examinations, which disables further operation of the vanes. Possible mistakes during the initial assessment of the engine condition result in huge costs due to unnecessary overhaul of the entire engine. Therefore, there is a need to apply non-destructive test methods to the maximum possible extent with the aim to evaluate the overheating status of the gas turbine vanes on a current basis. This paper outlines the non-destructive test methods that are currently in use and that are based on analysis of surface images obtained from the examined parts within the visible bandwidth of electromagnetic waves as well as on surface analysis of examined items with the use of a ring-wedge detector. Particular attention is paid to opportunities that enable unbiased diagnostics of changes in the microscopic structure of vanes by means of the non-destructive thermographic method as well the X-ray computer tomography.