The tracer grain-boundary diffusion of 63Ni, in slightly hypostoichiometric alloys which contained a few percent of Cr, Fe or Zr, was studied (table 22) by using serial sectioning and residual activity methods. Measurements of grain-boundary diffusivity were carried out temperatures of 873 to 1273K. It was found that the addition of Cr, Fe and Zr decreased the diffusivity, and increased the activation enthalpy of 63Ni.
Grain-Boundary Diffusion of Nickel in Cr-, Fe- and Zr-Modified Ni3Al Intermetallic. Cermak, J., Ruzickova, J., Pokorna, A.: Intermetallics, 1999, 7[6], 725-30
Table 22
Arrhenius parameters for 63Ni grain-boundary diffusion in Ni3Al alloys
Alloy | Po(m3/s) | E(kJ/mol) |
Ni75.3Al24.7 | 1.38 x 10-13 | 161.7 |
Ni73.3Al22.8Fe3.9 | 3.39 x 10-13 | 176.5 |
Ni70.8Al23.1Fe6.1 | 1.26 x 10-13 | 173.8 |
Ni73.9Al23.2Cr2.9 | 2.46 x 10-12 | 199.5 |
Ni71.5Al22.6Cr5.9 | 1.55 x 10-12 | 198.1 |
Ni76.4Al22.9Zr0.7 | 1.66 x 10-12 | 191.4 |
Ni76.1Al22.3Zr1.6 | 1.91 x 10-12 | 199 |
Table 23
Grain-boundary diffusivities of 63Ni in B-doped Ni3Al
Temperature (K) | Al(at%) | B(at%) | P(m3/s) |
1073 | 24.1 | 0 | 8.33 x 10-22 |
1073 | 25.5 | 0 | 1.61 x 10-21 |
1073 | 26.1 | 0 | 8.48 x 10-22 |
1013 | 24.1 | 0 | 2.88 x 10-22 |
1013 | 25.5 | 0 | 5.40 x 10-22 |
1013 | 26.1 | 0 | 1.79 x 10-22 |
953 | 24.1 | 0 | 6.05 x 10-23 |
953 | 25.5 | 0 | 5.29 x 10-23 |
953 | 26.1 | 0 | 3.29 x 10-23 |
893 | 24.1 | 0 | 1.09 x 10-23 |
893 | 25.5 | 0 | 5.33 x 10-24 |
893 | 26.1 | 0 | 8.42 x 10-24 |
833 | 24.1 | 0 | 6.43 x 10-25 |
833 | 25.5 | 0 | 9.30 x 10-25 |
833 | 26.1 | 0 | 1.51 x 10-24 |
773 | 24.1 | 0 | 6.27 x 10-26 |
773 | 25.5 | 0 | 4.28 x 10-26 |
773 | 26.1 | 0 | 6.79 x 10-26 |
1173 | 25.7 | 0.106 | 1.53 x 10-21 |
1073 | 24.0 | 0.106 | 6.76 x 10-22 |
1073 | 25.7 | 0.106 | 2.28 x 10-22 |
1073 | 26.8 | 0.106 | 2.85 x 10-22 |
1013 | 24.0 | 0.106 | 7.56 x 10-23 |
1013 | 25.7 | 0.106 | 4.23 x 10-23 |
1013 | 26.8 | 0.106 | 9.24 x 10-23 |
953 | 24.0 | 0.106 | 2.97 x 10-23 |
953 | 25.7 | 0.106 | 1.15 x 10-23 |
953 | 26.8 | 0.106 | 2.38 x 10-23 |
Table 23 (continued)
Grain-boundary diffusivities of 63Ni in B-doped Ni3Al
Temperature (K) | Al(at%) | B(at%) | P(m3/s) |
893 | 24.0 | 0.106 | 5.60 x 10-24 |
893 | 25.7 | 0.106 | 1.31 x 10-24 |
893 | 26.8 | 0.106 | 3.24 x 10-24 |
833 | 24.0 | 0.106 | 4.38 x 10-25 |
833 | 26.8 | 0.106 | 3.43 x 10-25 |
773 | 24.0 | 0.106 | 3.65 x 10-26 |
773 | 26.8 | 0.106 | 3.54 x 10-26 |
1073 | 24.4 | 0.268 | 1.39 x 10-22 |
1073 | 25.5 | 0.268 | 1.13 x 10-22 |
1073 | 26.5 | 0.268 | 1.17 x 10-22 |
1013 | 24.4 | 0.268 | 2.70 x 10-23 |
1013 | 25.5 | 0.268 | 1.97 x 10-23 |
1013 | 26.5 | 0.268 | 4.57 x 10-23 |
953 | 24.4 | 0.268 | 8.54 x 10-24 |
953 | 25.5 | 0.268 | 4.59 x 10-24 |
953 | 26.5 | 0.268 | 5.82 x 10-24 |
893 | 24.4 | 0.268 | 1.17 x 10-24 |
893 | 25.5 | 0.268 | 5.81 x 10-25 |
893 | 26.5 | 0.268 | 7.94 x 10-25 |
833 | 24.4 | 0.268 | 1.28 x 10-25 |
833 | 25.5 | 0.268 | 9.46 x 10-26 |
833 | 26.5 | 0.268 | 1.83 x 10-25 |
773 | 24.4 | 0.268 | 5.97 x 10-27 |
773 | 25.5 | 0.268 | 3.68 x 10-27 |
773 | 26.5 | 0.268 | 5.98 x 10-27 |