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Diffusion and segregation of niobium in fcc-nickel
Ist Teil von
Journal of physics. Condensed matter, 2012-03, Vol.24 (9), p.095010-10
Ort / Verlag
Bristol: IOP Publishing
Erscheinungsjahr
2012
Link zum Volltext
Quelle
MEDLINE
Beschreibungen/Notizen
Niobium is one of the major alloying elements, among the refractory elements, contributing to the strengthening of superalloys. Consequently, data about its behavior and its migration mechanism in fcc-Ni are essential knowledge to understand and control the strengthening in such alloys. We present in this work Nb interactions, solubility and diffusion in Ni performed by using the GGA approximation of the density functional theory. The substituted site is found to be the most favorable configuration in comparison to the tetrahedral and octahedral sites. The effect of temperature on solubility is discussed taking into account the thermal expansion of the lattice parameter and the vibrational contribution. Its diffusion mechanism is also discussed and compared to the literature. We finally discuss the segregation of Nb atoms on a Σ5-(012) symmetric tilt grain boundary.