Microstructural and Metallurgical Characterization of Prematurely retired PT6A-114A High Pressure (HP) Compressor Turbine (CT) Blades used for Short- Haul Aircrafts

Abstract

This paper presents microstructural and metallurgical characterization of prematurely retired from service high pressure (HP), PT6A-114A engine CT blades at 6378 creep-fatigue hours against a preset 10000 creep-fatigue hours. Sample preparation entailed; sectioning, mounting, grinding, polishing and carbon coating. A detailed microstructural and metallographic characterization was then performed on the prepared samples using x-ray florescence (XRF), x-ray diffraction (XRD) and scanning electron microscopy (SEM) on the material. The XRF results affirmed the existence of the bulk constituent elements that matched the manufacturers’ specification. The XRD analyses enabled positive identification of the resultant compounds which constituted the protective coating and the substrate material. The SEM results established that the protective coating of the tips was more attacked compared to the airfoils and the bases and as a result, the substrate material equally degraded. Keywords—Inconel 713LC, x-ray florescence, x-ray diffraction, energy dispersive spectroscope-scanning electron microscopy.