EBSD Characterization of Pure Iron Deformed by ECAE

摘要

Polycrystalline iron was deformed by eight ECAE passes using the route B_c to a total strain of 9.2. After deformation the material was annealed at temperatures up to 800°C. Scanning electron microscopy (SEM) and high-resolution electron backscatter diffraction (EBSD) were used to characterize both deformed and annealed structures. In the as-deformed state, the mean grain size is 650 nm and the volume fraction of high angle boundaries (V_(HAB)) is 56%. Upon annealing there is a pronounced softening above 300°C. At the beginning of recrystallization, at about 400°C, the V_(HAB) increases to 71%. The results indicate that discontinuous recrystallization is the main softening mechanism in severely deformed iron.