부산대학교 도서관

Three case studies were reported, which demonstrate the application of electron backscatter diffraction technique in order to clear up the nature and main patterns of structural transformations at large plastic strains. The cases considered relate to the microstructure evolution in aluminum under extremely high strain rates as well as the formation of deformation-induced boundaries in iron under necking. Based on the crystallographic analysis of deformation structure, it has been shown that deformation twinning occurs in aluminum in the form of mesoscale bands. Such twins make significant contribution to the structure formation when processing aluminum by dynamic channel angular pressing and when bonding aluminum plates by explosive welding. The analysis of angular deviations from the ideal twin misorientation allows evaluating, at which stage of deformation the twins had been nucleated. The study of structure evolution inside the neck of iron tensile specimen showed that deformation-induced high-angle boundaries, which serve as the preferential sites for the void nucleation, appear at a true strain about 1, mainly through formation of shear microbands. [ABSTRACT FROM AUTHOR]