Effects of rhenium addition on the temporal evolution of the nanostructure and chemistry of a model Ni-Cr-Al superalloy. I: Experimental observations

摘要

The temporal evolution of the nanostructure and chemistry of a model Ni-8.5 at. Cr-10 at. A alloy, with the addition of 2 at. Re, aged at 1073 K from 0.25 to 264 h, was studied. Transmission electron microscopy and atom-probe tomography were used to measure the number density and mean radius of the gamma' (L1(2) structure)-precipitates and the chemistry of the gamma'-precipitates and the gamma (face-centered cubic)-matrix, including the partitioning behavior of all alloying elements between the gamma- and gamma'-phases and the segregation behavior at gamma/gamma' interfaces. The precipitates remained spheroidal for an aging time of up to 264 h and, unlike commercial nickel-based superalloys containing Re, there was not confined (nonmonotonic) Re segregation at the gamma/gamma' interfaces. (c) 2006 Published by Elsevier Ltd on behalf of Acta Materialia Inc.