Book ChapterDOI
Evolution of Grain Boundary Precipitates in a Directionally Solidified Ni‐Base Superalloy during High Temperature Creep
TLDR
In this paper, the evolution of grain boundary phases during high temperature creep has been systematically investigated in a directionally solidified Ni-base superalloy, and the phase transformation between M23(C,B)6 and M5BB3 is thought to correlate strongly with the strain rate of different creep stages.Abstract:
The evolution of grain boundary phases during high temperature creep has been systematically investigated in a directionally solidified Ni-base superalloy. At the primary creep stage, precipitation of nanosize M5BB3 boride from γ matrix and phase transformation from M23(C,B)6 borocarbide to M5B3B boride occur at grain boundaries. At the steady-state creep stage, precipitation of blocky M23(C,B)6 borocarbide and coarsening of M23(C,B)6 with the dissolution of M5BB3 boride occur at grain boundaries. At the tertiary creep stage, precipitation of M5B3B boride from γ matrix or phase transformation from M23(C,B)6 borocarbide to M5BB3 boride occur again at grain boundaries. The precipitation of M5B3B is due to diffusion of B atoms promoted by applied tensile stress during high temperature creep, and the phase transformation between M23(C,B)6 and M5BB3 is thought to correlate strongly with the strain rate of different creep stages.read more
Citations
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Journal ArticleDOI
Improvement of grain boundary tolerance by minor additions of Hf and B in a second generation single crystal superalloy
TL;DR: In this article, a double-seed solidification technique with two misorientation levels, i.e., 5° and 20°, was used to produce a series of bicrystal superalloys with different contents of Hf and B.
References
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Book
The Superalloys: Fundamentals and Applications
TL;DR: In this paper, the physical metallurgy of nickel and its alloys is discussed and single crystal superalloys for blade applications for turbine disc applications are discussed. And the role of coatings is discussed.
Journal ArticleDOI
Effect of boron on grain-boundaries in Ni3Al†
TL;DR: In this paper, the effects of boron additions on grain-boundary chemistry and tensile properties of Ni3Al containing 24-26 at.% Al were studied, and the results suggest that alloy stoichiometry strongly influences grain-body chemistry, which in turn affects the grainboundary cohesion.
Journal ArticleDOI
On the kinetics of rafting in CMSX-4 superalloy single crystals
TL;DR: In this paper, the kinetics of γ′ rafting in single crystals at 950°C have been studied using scanning and transmission electron microscopies, and it is concluded that the threshold strain is a quantity suitable for distinguishing between rafting occurring in the “elastic� and “plastic” regimes.
Journal ArticleDOI
Grain boundary accommodation of slip in Ni3Al containing boron
TL;DR: In this article, it was shown that the addition of 750 ppm by weight (0.35 at%) of boron to stoichiometric Ni3Al reduces the effectiveness with which grain boundaries strengthen the alloy.
Related Papers (5)
HIGH TEMPERATURE CREEP OF A DIRECTIONALLY SOLIDIFIED Ni-BASE SUPERALLOY
Effects of grain refinement on creep properties of k417g superalloy
The nucleation of grain boundary voids in a nickel-base superalloy during high temperature creep
K. Shiozawa,Johannes Weertman +1 more