Afrl-rx-wp-tp-2010-4051 Measurement of Γ’ Precipitates in a Nickel- Based Superalloy Using Energy-filtered Transmission Electron Microscopy Coupled with Automated Segmenting Techniques

Precipitates of the ordered L12 ’ phase (dispersed in the face-centered cubic or FCC  matrix) were imaged in Rene 88 DT, a commercial multicomponent Ni-based superalloy, using energy filtered transmission electron microscopy (EFTEM). Imaging was performed using the Cr, Co, Ni, Ti and Al elemental L-edges in the energy loss spectrum. Manual and automated segmentation procedures were utilized for identification of precipitate boundaries, measurement of precipitate sizes and overall area fractions. The automated region growing technique for precipitate identification in images was determined to accurately measure precipitate diameters. In addition, the region growing technique provided a repeatable method for optimizing segmentation techniques for varying EFTEM conditions.