Nanoscale Characterization of Elemental Partitioning Between Gamma and Gamma Prime Phases in Rene 88DT Nickel Base Superalloy (Preprint)

摘要

The chemical partitioning of alloying elements between the disordered y and ordered y' phases in the nickel base superalloy Rene 88DT, has been characterized in detail using three dimensional atom probe tomography (3DAP) coupled with energy-filtered transmission electron microscopy studies. After a homogenization treatment followed by a water quench, it is observed that the morphology of the y' precipitates, reduces with increasing aging time, while the compositional gradient across the y/y' interface decrease. The process of growth of y' precipitates seems to occur through coalescence of adjacent y' precipitates, facilitated through the formation of 'necks' between adjacent precipitates. These necks are observed to have intermediate elemental concentration values, between the matrix and the y' precipitate compositions.