Advanced XRD System for NDI/E of SX Turbine Blades

Directionally solidified (DS) superalloy blades provided the basis for substantial gains in turbine engine performance in recent decades. Now, single crystal (SX) nickel-base alloy blades can be grown directionally with interior passages for cooling air, enabling more advances in engine performance and durability SX blades are composed of single crystals oriented parallel to one another span-wise, providing optimum strength, toughness and creep resistance. Problems arise when some grains grow off-axis, decreasing the blade strength. Mal-oriented grains (MOG) at the blade surface can be detected nondestructively using current Proto NDI/E systems. However, grain recrystallization may occur on the inside of hollow blades during production or during in-service flight operations. When recrystallized grains (RX) form on the inside surface of hollow blades, they are not detectable nondestructively by current inspection systemsan especially problematic and insidious condition. Based on recent research, Proto has developed a new approach to nondestructively inspect and evaluate hollow superalloy SX turbine blades. This approach exploits transmission topography (TT), advanced x-ray diffraction (XRD), precision collimation techniques and new detector technologies, while using COTS x-ray tubes. The Proto NDI/E system for SX turbines blades will be transportable for use in laboratory, production and depot facilities.