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Recent Advances in Making Nanometals by Heavy Plastic Deformation
Warsaw University of Technology, Faculty of Materials Science and Engineering (InMat), Wołoska 141, Warszawa 02-507, Poland
Nanometals defined as metals or alloys having grain size reduced to less than 100 nm have attracted a considerable research interest due to their advanced propertied such as very high strength combined with good ductility, increased high cycle fatigue life, enhanced charging capacity and diffusion rate of hydrogen, improved resistance to corrosion and wear. They can be produced following the bottom-up methods, e.g. consolidation of nanopowders, electrodeposition, nanocrystallization from amorphous phase. However, it seems that better technological perspectives are related top-down approach which consists in the transformation of metals or alloys having a conventional grain size into bulk materials possessing submicron- or nanoscaled structure by using the methods of severe plastic deformation (SPD). To date, a significant development in SPD techniques has been achieved and such methods as ECAP, HPT, ARB and CEC have been successfully applied to grain refinement in various materials.
The major challenge for nanometals is their commercialization. To achieve this goal a significant effort must be undertaken. The main restriction which limits the industrial application of nanometals is due to a small volume of obtained products. Therefore, there is a strong interest in development of new processing techniques. Recent results have shown that more conventional techniques such as rolling in liquid nitrogen or hydrostatic extrusion are also efficient in grain refinement and allow to obtain substantially greater volumes of products. Nanometals are known as high strength materials. However, the detailed description of other mechanical and physico-chemical properties and their stability during exploitation is essentials in order to introduce products made of nanometals into the market. Nanometals are unknown for industrial community. Some examples of potential application of nanometals will be shown.
Presentation: Invited at E-MRS Fall Meeting 2007, Acta Materialia Gold Medal Workshop, by Malgorzata Lewandowska
See On-line Journal of E-MRS Fall Meeting 2007
Submitted: 2007-07-22 11:02 Revised: 2009-06-07 00:44