Diffusion of Re and Ru in the γ′ Phase of Ni Based Alloys

Abstract

The diffusion of Re and Ru in the 0 -Ni 3 Al phase has been investigated at a range of temperatures 1423-1523 K by using the pseudo-binary diffusion couples. It was found that the concentration gradient of Re appeared to promote the uphill diffusion of Al, whereas that of Ru did not promote the Al uphill diffusion. The cross interdiffusion coefficients ofD D Ni AlRe andD D Ni AlRu were independent of the matrix ordering since they were comparable qualitatively between those in the 0 -Ni 3 Al and in the -Ni phases. The tracer diffusion coefficients for Re and Ru in Ni 3 Al were estimated by extrapolation and the obtained activation energies were consistent with the site preferences of the elements reported in the literature. Further, the results of this work suggest that the diffusion of Ru in Ni 3 Al is mostly governed by the diffusion in Ni sublattice and the diffusion of Re is mainly controlled by the formation of anti-site defects in the Ni sublattice with negligible contribution of the anti-site bridge mechanism.

Diffusion of Ti, V and Nb in Ni₃Al at Elevated Temperatures

“…4. The self-diffusion coefficient of ruthenium (Ru) and renium (Re) in γ′ reported by Mabruri et al [11] is also displayed in Fig. 4 for comparison.…”

Diffusion of Al and Al-Substituting Elements in Ni₃Al at Elevated Temperatures

“…On the other hand, Ru exhibits comparable values both in the £ A and £ phases 15,18) which means that Ru diffuses in the £ A phase by a similar mechanism with that in the £ phase. The site occupancy of Ru in £ A phase in reported by Mabruri et al 15) Although the Ru site occupancy reported here is supported by some other authors, 2,11,1921) it is a speculation from the low and comparable activation energy values of Ru in both £ and £ A phases and further study is necessary for its verification. Figure 6 shows the variation of activation energies with the bond order of elements.…”

“…5. The intrinsic diffusion coefficient of ruthenium (Ru) and rhenium (Re) in the £ A phase reported by Mabruri et al 15) is also displayed in the figure for comparison. Mabruri used Darken-Manning equation 16,17) for the analysis of intrinsic diffusion coefficients.…”

Spin and spin–orbit coupling effects in nickel-based superalloys: A first-principles study on Ni3Al doped with Ta/W/Re

“…Many experiments were undertaken to understand the mechanical properties, [6][7][8][9] as well as the locations and diffusion of Ta, [10][11][12] W, [13,14] and Re [15,16] in superalloys. Ta and Re atoms prefer to substitute Al sites in γ phase, while W atoms show no preference and can appear in both γ and Al sites in γ phases.…”