کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1447866 | 988658 | 2010 | 10 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Grain boundary self-diffusion in polycrystalline nickel of different purity levels Grain boundary self-diffusion in polycrystalline nickel of different purity levels](/preview/png/1447866.png)
Grain boundary self-diffusion in Ni materials of two different purity levels (99.6 and 99.999 wt.%) was measured over wide temperature intervals using the radiotracer technique and applying the 63Ni radioisotope. The diffusion experiments were performed in both Harrison’s type B and type C kinetic regimes. The diffusional grain boundary width, δ, was found to be equal to 0.54 ± 0.1 nm, that is reasonably close to the accepted value of δ=0.5nm in face-centred cubic metals. The purer the material, the higher the grain boundary diffusivity and the lower the corresponding activation enthalpy of self-diffusion along general high-angle grain boundaries. Using the semi-empirical approach of Borisov et al., the average energy of high-angle grain boundaries was estimated to be about 0.79 and 0.98 J m−2 in the low- and high-purity Ni materials at room temperature, respectively.
Journal: Acta Materialia - Volume 58, Issue 2, January 2010, Pages 386–395