The tracer grain-boundary diffusion of 51Cr in slightly hypostoichiometric (less than 25at%Al) alloys, which contained several at% of Fe, Cr and Zr, was studied by using serial sectioning and residual activity methods. Measurements of the diffusion coefficient in the grain boundary, and of the width of the grain boundary, were carried out at 773 to 1273K (table 9). It was found that the addition of up to about 6at% of Fe or Cr did not affect the Cr grain-boundary diffusion. On the other hand, the addition of a small amount of Zr tended to increase the activation enthalpy and pre-exponential factor for Cr grain-boundary diffusion.
Grain-Boundary Diffusion of Chromium in Ni3Al Intermetallic Modified by Fe, Cr and Zr. Cermak, J., Ruzickova, J., Pokorna, A.: Intermetallics, 1998, 6[5], 437-43
Table 9
Grain-boundary diffusivity of 51Cr in Ni3Al alloys
Alloy | Temperature (K) | Method | P(m3/s) |
Ni75.3Al24.7 | 1273 | serial sectioning | 1.94 x 10-20 |
Ni75.3Al24.7 | 1273 | residual activity | 2.02 x 10-20 |
Ni75.3Al24.7 | 1073 | serial sectioning | 6.28 x 10-22 |
Ni75.3Al24.7 | 1073 | residual activity | 6.91 x 10-22 |
Ni75.3Al24.7 | 998 | serial sectioning | 8.79 x 10-23 |
Ni75.3Al24.7 | 998 | residual activity | 1.08 x 10-22 |
Ni75.3Al24.7 | 923 | serial sectioning | 8.81 x 10-24 |
Ni75.3Al24.7 | 923 | residual activity | 1.49 x 10-23 |
Ni75.3Al24.7 | 848 | serial sectioning | 1.62 x 10-24 |
Ni75.3Al24.7 | 848 | residual activity | 1.11 x 10-24 |
Ni75.3Al24.7 | 773 | serial sectioning | 1.78 x 10-25 |
Ni73.3Al22.8Fe3.9 | 1273 | serial sectioning | 2.51 x 10-20 |
Ni73.3Al22.8Fe3.9 | 1273 | residual activity | 3.91 x 10-20 |
Ni73.3Al22.8Fe3.9 | 1073 | serial sectioning | 9.10 x 10-22 |
Ni73.3Al22.8Fe3.9 | 1073 | residual activity | 1.19 x 10-21 |
Ni73.3Al22.8Fe3.9 | 998 | serial sectioning | 1.50 x 10-22 |
Ni73.3Al22.8Fe3.9 | 998 | residual activity | 4.85 x 10-22 |
Ni73.3Al22.8Fe3.9 | 923 | serial sectioning | 6.43 x 10-24 |
Ni73.3Al22.8Fe3.9 | 923 | residual activity | 4.08 x 10-23 |
Ni73.3Al22.8Fe3.9 | 848 | serial sectioning | 1.67 x 10-24 |
Ni73.3Al22.8Fe3.9 | 848 | residual activity | 1.54 x 10-24 |
Ni73.3Al22.8Fe3.9 | 773 | serial sectioning | 9.11 x 10-26 |
Ni73.3Al22.8Fe3.9 | 773 | residual activity | 3.30 x 10-25 |
Ni70.8Al23.1Fe6.1 | 1273 | residual activity | 2.68 x 10-20 |
Ni70.8Al23.1Fe6.1 | 1073 | serial sectioning | 1.10 x 10-21 |
Table 9 (continued)
Grain-boundary diffusivity of 51Cr in Ni3Al alloys
Alloy | Temperature (K) | Method | P(m3/s) |
Ni70.8Al23.1Fe6.1 | 1073 | residual activity | 3.60 x 10-22 |
Ni70.8Al23.1Fe6.1 | 998 | serial sectioning | 9.05 x 10-23 |
Ni70.8Al23.1Fe6.1 | 998 | residual activity | 2.22 x 10-22 |
Ni70.8Al23.1Fe6.1 | 923 | serial sectioning | 2.06 x 10-23 |
Ni70.8Al23.1Fe6.1 | 923 | residual activity | 3.78 x 10-23 |
Ni70.8Al23.1Fe6.1 | 848 | serial sectioning | 1.59 x 10-24 |
Ni70.8Al23.1Fe6.1 | 848 | residual activity | 3.09 x 10-24 |
Ni70.8Al23.1Fe6.1 | 773 | serial sectioning | 1.26 x 10-25 |
Ni70.8Al23.1Fe6.1 | 773 | residual activity | 1.76 x 10-25 |
Ni73.9Al23.2Cr2.9 | 1273 | residual activity | 1.01 x 10-20 |
Ni73.9Al23.2Cr2.9 | 1073 | serial sectioning | 3.34 x 10-22 |
Ni73.9Al23.2Cr2.9 | 1073 | residual activity | 3.83 x 10-22 |
Ni73.9Al23.2Cr2.9 | 998 | serial sectioning | 9.31 x 10-23 |
Ni73.9Al23.2Cr2.9 | 998 | residual activity | 3.72 x 10-23 |
Ni73.9Al23.2Cr2.9 | 923 | serial sectioning | 7.61 x 10-24 |
Ni73.9Al23.2Cr2.9 | 923 | residual activity | 1.80 x 10-23 |
Ni73.9Al23.2Cr2.9 | 848 | serial sectioning | 1.12 x 10-24 |
Ni73.9Al23.2Cr2.9 | 848 | residual activity | 1.48 x 10-24 |
Ni73.9Al23.2Cr2.9 | 773 | serial sectioning | 9.45 x 10-26 |
Ni71.5Al22.6Cr5.9 | 1073 | residual activity | 2.02 x 10-21 |
Ni71.5Al22.6Cr5.9 | 998 | serial sectioning | 1.19 x 10-22 |
Ni71.5Al22.6Cr5.9 | 998 | residual activity | 3.88 x 10-22 |
Ni71.5Al22.6Cr5.9 | 923 | serial sectioning | 3.19 x 10-23 |
Ni71.5Al22.6Cr5.9 | 923 | residual activity | 1.72 x 10-23 |
Ni71.5Al22.6Cr5.9 | 848 | residual activity | 3.82 x 10-24 |
Ni71.5Al22.6Cr5.9 | 773 | residual activity | 3.53 x 10-25 |
Ni76.4Al22.9Zr0.7 | 1273 | serial sectioning | 5.90 x 10-20 |
Ni76.4Al22.9Zr0.7 | 1273 | residual activity | 6.74 x 10-20 |
continued
Table 9 (continued)
Grain-boundary diffusivity of 51Cr in Ni3Al alloys
Alloy | Temperature (K) | Method | P(m3/s) |
Ni76.4Al22.9Zr0.7 | 1073 | serial sectioning | 8.77 x 10-22 |
Ni76.4Al22.9Zr0.7 | 1073 | residual activity | 1.10 x 10-21 |
Ni76.4Al22.9Zr0.7 | 998 | serial sectioning | 7.86 x 10-23 |
Ni76.4Al22.9Zr0.7 | 998 | residual activity | 1.51 x 10-22 |
Ni76.4Al22.9Zr0.7 | 923 | serial sectioning | 9.60 x 10-24 |
Ni76.4Al22.9Zr0.7 | 923 | residual activity | 1.24 x 10-23 |
Ni76.4Al22.9Zr0.7 | 848 | serial sectioning | 1.11 x 10-24 |
Ni76.4Al22.9Zr0.7 | 848 | residual activity | 1.30 x 10-24 |
Ni76.4Al22.9Zr0.7 | 773 | serial sectioning | 3.23 x 10-26 |
Ni76.1Al22.3Zr1.6 | 1073 | serial sectioning | 7.07 x 10-22 |
Ni76.1Al22.3Zr1.6 | 1073 | residual activity | 1.21 x 10-21 |
Ni76.1Al22.3Zr1.6 | 998 | serial sectioning | 2.95 x 10-22 |
Ni76.1Al22.3Zr1.6 | 998 | residual activity | 2.11 x 10-22 |
Ni76.1Al22.3Zr1.6 | 923 | serial sectioning | 6.29 x 10-24 |
Ni76.1Al22.3Zr1.6 | 923 | residual activity | 2.41 x 10-23 |
Ni76.1Al22.3Zr1.6 | 848 | serial sectioning | 1.06 x 10-24 |
Ni76.1Al22.3Zr1.6 | 848 | residual activity | 1.04 x 10-24 |
Ni76.1Al22.3Zr1.6 | 773 | serial sectioning | 2.60 x 10-26 |
Ni76.1Al22.3Zr1.6 | 773 | residual activity | 2.27 x 10-25 |