- Fabrication of nanocrystalline ferrite by heavy deformation
Nanocrystalline materials are polycrystals with a crystalline size less than 100 nm (typically 5-50 nm, 1nm = 10-9m). This type of material has found to possess novel properties quite different from conventional polycrystalline materials with coarse crystals (typically several tens of micrometers). Intensive researches on the production, structure characterization and properties of nanocrystalline materials have been carried out since 1984 and a variety of nanocrystalline materials have been produced by inert gas condensation, chemical vapor deposition, physical vapor deposition, mechanical alloying, etc.
In our laboratory, efforts have been made to produce nanocrystalline Fe-C alloys through heavy deformation process. Since Fe-C alloys, known as steels, are the most popular alloys applied all over the world, the significance of producing steels with nanocrystalline structure is great to either academic research and practical application. In the present stage, processes such as ball milling, weight drop test, cold rolling, etc., are being carried out on pure iron, martensite, ferrite and spheroidite. We have succeeded in producing nanocrystalline ferrite through ball milling in the above Fe-C alloys. The detailed microstructure characterization and mechanical properties of the obtained nanocrystalline ferrite are under investigation.
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