STATISTICALLY RELIABLE EBSD ANALYSIS METHOD OF GRAIN BOUNDARY CHARACTERIZATION

摘要

To understand the physics of recrystallization or grain growth, the orientation relation of the deformed grain and the recrystallized grain should be characterized in a sense of the measurement accuracy and the statistically reliability. To trace the change of the orientation relation during recrystallization, it is necessary to get out the orientation between the deformed and recrystallized grains. An easy angle/axis representation, called o-MDF(Overlaid Misorientation Distribution Function), is introduced to understand the orientation relation easily. The numerical algorithm is adopted public EBSD analysis program REDS. Anew parameter P_N is proposed to decide the statistical reliability of EBSD measurement map size. P_N denotes the change of the physical parameter due to the increase of the measurement pixel number. The proposed method is applied to the partially recrystallized IF steel. In case of the recrystallization of IF steel, the statistically reliable map size can be 512×512, where the number of grain is minimum 5.000 or safely 10,000. The frequency-misorientation diagram in the partially recrystallized IF steel shows two peaks, one is near 10° orientation relation relates with continuous recrystallization of γ-fiber and another is 55° orientation relation relates with γ -fiber from α-fiber.