|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Gamma (FCC)/Gamma-Prime (L12) Co-Based Superalloys II
||Coarsening Kinetics and Elemental Partitioning of (f.c.c.) Gamma Plus (L12) Gamma-prime-strengthened Co-base Superalloys
||Daniel Sauza, Peter J Bocchini, James Coakley, Eric A Lass, David C Dunand, David N Seidman
|On-Site Speaker (Planned)
||David N Seidman
The emergence of Co-base superalloys with a microstructure consisting of (L12) gamma-prime precipitates in a (f.c.c.) gamma matrix presents an exciting opportunity for the development of a new class of high-temperature structural alloys. Optimized Ni-base superalloys, which contain an analogous microstructure, may contain 10-12 elemental additions, necessitating a thorough understanding of alloying effects on the Co-Al-W system. 3D picosecond ultraviolet laser-assisted local-electrode atom-probe (LEAP) tomography and scanning electron microscopy are utilized to investigate the temporal evolution and elemental partitioning behavior of several model Co-Al-W-X alloys. The coarsening kinetics of the (L12) gamma-prime precipitates are determined via multivariate regression analyses from the experimental measurements, and the resulting temporal exponents show good agreement with the predictions of Lifshitz-Slyozov-Wagner and Philippe-Voorhees models. LEAP tomography is utilized to investigate the elemental partitioning behavior of a Co-30Ni-7Al-2W-3Mo-2Nb-1Ta at.% alloy with a high (L12) gamma-prime solvus temperature (1227 °C) and small W-content for reduced bulk density.