Combining neutron diffraction and imaging for residual strain measurements in a single crystal turbine blade

Abstract

Neutron diffraction is a technique often used for the non-destructive characterization of residual stresses in engineering materials and components. Measuring stresses within partially hollow objects with complex internal geometry however is challenging due to the difficulties of accurately placing the measurement gage volume in relation to the internal structures. In this study this difficulty is overcome combining surface metrology and neutron tomography to guide the neutron diffraction measurements. Using this technique the triaxial residual strain variations across the airfoil in a single crystal nickel-based superalloy turbine blade have been measured.