Evolution and Analysis of Microstructures Related to Super Alloys of Engine Turbine Blades

Abstract

The integrity and performance of turbine blades in aircraft engines are paramount to the safety and efficiency of air operations, particularly in demanding environments such as combat and training missions. These components, crafted from single-crystal Ni-based superalloys, endure a range of stresses, including compressive and torsional forces, and extreme temperature fluctuations. Environmental factors like sand, dust, and humidity further exacerbate degradation, manifesting as dents, erosion, and tears, leading to significant microstructural changes. Despite the critical nature of these phenomena, there is a notable gap in the scientific literature regarding the empirical analysis of microstructural changes in turbine blades under varied operational scenarios.

This research aims to bridge this gap by employing advanced analytical techniques such as Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), X-Ray Diffraction (XRD), and detailed image processing. The study meticulously examines the degradation patterns and microstructural transformations in high-pressure turbine (HPT) blades made of single-crystal Ni-based superalloys. SEM's high resolution and depth of field provide profound insights into crystalline alterations at the microlevel, enabling a detailed assessment of the blades' structural integrity over their operational lifecycle. EDX offers elemental composition analysis, while XRD identifies phase changes and crystallographic structures.

The results reveal detailed rafting parameters and the evolution of γ (gamma), γ' (gamma prime), and γ'' (gamma double prime) phases over the service life of the blades. These findings elucidate the relationship between thermal loads, service conditions, and microstructural stability. Such microstructural changes directly impact the mechanical properties, including strength, creep resistance, and oxidation resistance of the material. Understanding these degradation mechanisms allows for the optimization of material processing and manufacturing techniques, aiming to enhance the stability and performance of Ni-based superalloys.