Two-Dimensional Observation of Grain Movements in Elongated and Aligned Grain Structure during High Temperature Deformation

Abstract

It is understood that grains move by grain boundary sliding, and change their relationship to each other during superplastic deformation. Ideal two-dimensional observation of grain movements from the specimen surface is difficult even in the shear deformation because grains move three-dimensionally according to the stress distribution against the specimen surface. In this study, ODS steel with elongated grains aligned along one direction was deformed perpendicular to the aligned axis to achieve ideal two-dimensional grain movements. Surface height profiles with a laser microscope showed small amount of three-dimensional grain movements, while two-dimensional grain movements and rotations were appeared by observations before and after the deformation with SEM-EBSD.