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arXiv · 0710.3610

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

Chantal K. Sudbrack·Tiffany D. Ziebell·Ronald D. Noebe·David N. Seidman
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Abstract

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.

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Chantal K. Sudbrack, Tiffany D. Ziebell, Ronald D. Noebe, David N. Seidman. 2007-10-18. Effects of a tungsten addition on the morphological evolution, spatial correlations, and temporal evolution of a model Ni-Al-Cr superalloy. https://arxiv.org/abs/0710.3610

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