Non-destructive Volumetric Methods for Detection of Recrystallized (RX) Grains in Single-Crystal (SX) Aerospace Components

Single-crystalSingle-crystal (SX) nickel-based superalloysNickel-based superalloy are used as blade materials for gas turbine aircraft engines due to their superior mechanical and environmental performance. These properties of SX superalloysSuperalloys depend highly upon their crystallographic orientations. The SX superalloySuperalloys components contain no large angle boundaries, which excludes intergranular oxidationOxidation and rupture. However, the industrial manufacturing of SX superalloySuperalloys blades can still result in the formation of recrystallized (RX) grains which can significantly limit the life of these components. The RX grains can form anywhere within a SX blade but are most frequently observed in areas of high geometrical complexity. These are often areas where high thermal stresses occur during solidificationSolidification and subsequent cooling processes due to significant mechanical constraint between shell/core materials and airfoil and can occur on the interior walls of hollow configurations. Focused research efforts have been conducted to develop and demonstrate a non-destructive method for volumetric analysis and detection of RX grains in SX components. This method is being further developed and deployed via an integrated computational materials engineeringIntegrated computational materials engineering approach to further identify and control critical quality material and processingProcessing parameters to mitigate such features in the most complex production castings. Implementation of this advanced non-destructive evaluation process will be reviewed in terms of targeted locations based on probabilistic material and process modeling.