The Centre of Excellence in Steel Technology, IIT Bombay organised the lecture of the “Steel Colloquium Series” on Monday, December 11, 2017. The lecture on “Ways to Fabricate Ultrafine Grained Steels” was delivered by Prof. Nobuhiro Tsuji, Professor, Kyoto University.
Prof. Tsuji teaches at the Department of Materials Science and Engineering at the Kyoto University. His major research areas include Structural Metallic Materials (steels and non-ferrous alloys), Bulk Nanostructured Metals, Microstructure of Materials, Mechanical Properties of Materials, Metalworking Process, Physical Metallurgy and Mechanical Metallurgy. He obtained his Bachelors, Masters and PhD degrees from Kyoto University. He is a member of several professional societies including Japan Institute of Metals and Iron and Steel Institute of Japan. He has published more than 300 papers and 24 book chapters.
Below is a brief abstract of the lecture:
Ultrafine grained (UFG) metallic materials of which mean grain sizes are smaller than 1 micron have been studied energetically since it was found that ultra-high strain deformation (severe plastic deformation: SPD) could realize UFG structures in almost all metallic materials. However, it is still difficult to apply the SPD processes, which require special equipment and a little bit complicated procedures, to large-scale fabrication of bulky metals, typically in steel industries.
In this talk, Prof. Tsuji showed the mechanism why UFG microstructures could be obtained by SPD firstly, and then introduced the original processes for realizing UFG structures in steels without SPD, which are developed in his group and applicable to conventional thermomechanical processing routes. In some cases the fully recrystallized UFG structures which were favorable for both strength and ductility could be obtained.