Effects of a tungsten addition on the morphological evolution, spatial correlations, and temporal evolution of a model Ni-Al-Cr superalloy

Autor: Sudbrack, Chantal K., Ziebell, Tiffany D., Noebe, Ronald D., Seidman, David N.
Rok vydání: 2007
Předmět:
Druh dokumentu: Working Paper
Popis: The effect of adding 2 at.% W to a model Ni-Al-Cr superalloy on the morphological evolution, spatial correlations and temporal evolution of g'(L12)-precipitates at 1073 K is studied with scanning electron microscopy and atomic force microscopy. Adding W yields a larger microhardness, earlier onset of spheroidal-to-cuboidal precipitate morphological transition, larger volume fraction (from ~20 to 30%), reduction in coarsening kinetics by one third and a larger number density (Nv) of smaller mean radii () precipitates. The kinetics of and interfacial area per unit volume obey t1/3 and t-1/3 relationships, respectively, which is consistent with coarsening driven by interfacial energy reduction. The Nv power law dependencies deviate, however, from model predictions indicating that a stationary-state is not achieved. Quantitative analyses with precipitate size distributions, pair correlation functions, and edge-to-edge interprecipitate distance distributions gives insight into 2D microstructural evolution, including the elastically driven transition from a uniform g'-distribution to one-dimensional <001>-strings to eventually clustered packs of g'-precipitates in the less densely packed Ni-Al-Cr alloy.
Comment: in-press, Acta Materialia: 44 pages, 15 figures (double spaced Word document)
Databáze: arXiv
Externí odkaz: