Many studies have been conducted so far for grain refinement in various kinds of steels in order to improve strength-toughness balance. Especially, for the last decade, tremendous efforts have been made throughout the world to refine grains down to 1 μm in steels. Upon such backgrounds, the International Symposium on Ultrafine Grained Steels (ISUGS) was initiated by The Iron and Steel Institute of Japan (ISIJ) first in Fukuoka in 2001 in order to discuss fabrication process, microstructure characterization and mechanical properties of ultrafine grained steels. The 2nd and 3rd symposiums were held in Geelong, Australia and in Hainan Island, China in which the other metallic materials are covered as well as steels. During this period, physical metallurgy of ultrafine grained steels has advanced with particular interests on structure-property-processing relationship. Microstructure characterization and mechanical properties of ultrafine grained steels produced by various routes with phase transformation, deformation and recrys-tallization have been studied extensively. In addition, a considerable amount of focus has been placed on strength, elongation, toughness, and their trade-off balancing. Very recently much attention has been given to enlarge process windows for exploring the commercial production of bulky ultrafine grained materials.
展开▼
