Institute of Metal Research, Chinese Academy of Sciences,
Keywords: bulk nanocrystalline metallic materials, corrosion, mechanical properties, severe rolling technology
Summary:The concept of nanocrystalline metallic materials was put forward by Prof. Gleiter in 1980s . From then on, nanocrystlline metallic materials have been extensively studied by the scientists all over the world . The first and key problem that we should solve in the fundamental research and application of nanocrystalline metallic materials is the production of nanocrystalline metallic materials because the production technique for nanocrystalline metallic materials can determine the cost of production and the dimension of bulk nanocrystalline metallic materials, and their different properties, such as mechanics , corrosion  and thermodynamics  et al. Many production techniques for nanocrystalline metallic materials have been proposed by scientists, such as crystallization of amorphous alloys , severe plastic deformation , accumulative roll-bonding  et al. However, one property of nanocrystalline metallic materials was usually improved at cost another property in many published papers . However, we proposed another production technique for bulk nanocrystalline metallic materials which was called as severe rolling technique . After our investigation of bulk nanocrystalline metallic materials prepared by severe rolling technique for many years from 2002 to now, we could concluded that the features of this production technology are (1) this production technology can be industrialized because all the bulk nanocrystalline metallic materials, such as bulk nanocrystalline 304 stainless steel, ingot iron, industrial pure Al, 3003 Al alloy and 1Cr13 alloy studied in our group were prepared in steel factory rather than in laboratory; (2) the same property (such as corrosion resistance) of different bulk nanocrystalline metallic materials (such as ingot iron, industrial pure Al and 304 stainless steel) can be improved [11-13] as shown in Figs. 1-2; (3) the different properties (such as high-temperature oxidation, electrochemical corrosion) of the same bulk nanocrystalline metallic material (such 304 stainless steel) can be also enhanced [14-15] as shown in Figs. 1 and 3; (4) the cost of production is low due to its potential industrialization. The cost of production and the properties of bulk nanocrystalline metallic materials are the two key issues for their application. In actual application of metallic materials, the simultaneously enhanced several properties were usually required. Therefore, we believe that both the scientists in materials science and the customer of metallic materials should be interested in the bulk nanocrystalline metallic materials prepared by severe rolling technology because the bulk nanocrystalline metallic materials prepared by this production technique can simultaneously improve their several properties with low cost. In the same time, the investigation of bulk nanocrystalline metallic materials produced by severe rolling technology may provide us the possible opportunity to discover the new mechanisms of different performances and to obtain the optimized processing technology for bulk nanocrystalline metallic materials.