Atom Probe Tomography of the VV751P Nickel-Based Superalloy

This work presents the results of the study of three different blanks used for the production of disks for gas-turbine engines made of a granular Ni-based superalloy. The blanks differed in the heat treatments performed and in the complexes of mechanical characteristics. The scanning electron microscopy of the studied materials showed that the size of the gamma-matrix grains was 30-50 micrometers. In addition, particles of the gamma and gamma' phases with a size from 10 to 70 nm were revealed in the volumes of all blanks. The morphology of these particles has been studied. Within the particles of the gamma' phase, homogeneously distributed equiaxed clusters of atoms of gamma-forming elements were revealed with a size of 1-4 nm and flattened clusters of the same size and the same chemical composition aligned into chains. In the particles of both phases and in the transition layers between them, concentrations of the alloying components and impurities have been determined. In the studied volumes of the three different blanks of the disks, the volume fractions of the gamma' phase were found to be 68 +/- 1, 61 +/- 2, and 62 +/- 4%.