Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8160312 | Physica B: Condensed Matter | 2018 | 21 Pages |
Abstract
Evolution of lattice characteristics in ordered γⲠand γ phases affected by Ta/W ratio was investigated in experimental Ni-base superalloys. Experimental analysis using Energy Dispersive Spectroscopy (EDS) and X-Ray Diffraction (XRD) and theoretical calculations illustrated that the ordering degree can be enhanced by the substitution of Ta for Al sites in the γâ²-Ni3(Al,Ta) lattice. A gradual increase in Ta/W ratio led to a noticeable increase in atomic ordering degree of γâ²-Ni3(Al,Ta) precipitates and the intensity values of the γⲠsuperlattice peaks normalized to that of the γ+γⲠfundamental peaks in XRD patterns. EDS elemental analyses indicated that this phenomenon was associated with Ta atoms occupying Al sites in Ni3(Alx,Ta1-x) superlattice and raise its ordering tendency. Deconvolution of overlapped γ+γⲠXRD peaks indicated that γⲠlattice constant varies with the concentrations of Ta and Al. Furthermore, increasing Ta/W content up to 0.5 leads to substitution of Al and Ta for W atoms in the ordered γⲠlattice. Also, by increasing Ta/W ratio far from 0.5, Ta atoms substitute for Al and W atoms. Meanwhile, γ/γⲠlattice misfit and lattice parameters of ordered γⲠvaried systematically with Ta, W and Al contents of γⲠsuperlattice.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
M. Mostafaei, S.M. Abbasi,