Grain growth of nanocrystalline Ni powders prepared by cryomilling
SCIE
SCOPUS
- Title
- Grain growth of nanocrystalline Ni powders prepared by cryomilling
- Authors
- Lee, J; Zhou, F; Chung, KH; Kim, NJ; Laverina, EJ
- Date Issued
- 2001-12
- Publisher
- MINERALS METALS MATERIALS SOC
- Abstract
- Grain growth of nanocrystalline Ni powders with an average grain size of similar to 22 nm prepared by cryogenic mechanical milling (or cryomilling) was investigated by using X-ray diffraction (XRD) and transmission electron microscopy (TEM). A dispersion of NiO and Ni3N particles with a size less than 5 nm was formed in the cryomilled powders. The Ni3N particles decomposed at 773 K. It was found that at 0.56 homologous temperature (T/T-M), Ni grains were retained at similar to 150 nm even after long annealing times (e.g., 4 hours). For 0.45 to 0.62 T/T-M, the time exponent n deduced from D-1/n - D-0(1/n) = kt was 0.16 to 0.32, tending toward 0.5 as T/T-M increased. The activation energy for grain growth in the Ni sample was determined to be 113 kJ/mol, which is close to the activation energy for grain boundary self-diffusion in polycrystalline Ni. The observed high grain size stability was attributed primarily to a grain boundary pinning mechanism arising from the NiO particles as well as impurity segregation.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/11446
- DOI
- 10.1007/s11661-001-0185-8
- ISSN
- 1073-5623
- Article Type
- Article
- Citation
- METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, vol. 32, no. 12, page. 3109 - 3115, 2001-12
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