Effect of the magnitude of sub-boundary angles on the abnormal grain growth rate of Goss grains in Fe-3%Si steel

In spites of extensive studies, the selective abnormal grain growth (AGG) of Goss grains in Fe-3%Si steel remains still unclear. Here, the effect of the magnitude of sub-boundary angles on AGG behavior was investigated both by computer simulations and experiments. In 3-dimensional Monte Carlo simulations of grain growth based on the realistic grain boundary energy distribution data, the grains of Goss orientation, which are given the subboundaries, grew abnormally and smaller sub-boundary energies resulted in larger Goss grains. Additionally, a Fe-3%Si steel, after primary recrystallization, was heated to 1050 degrees C to induce AGG. Measurements of subboundary angles for three different sizes of abnormally growing Goss grains by synchrotron X-ray microdiffraction after the initial stage of secondary recrystallization showed that the misorientation of the subboundary angles was 0.41 degrees for the small Goss grain of 734 mu m. Moreover, the average misorientation of subboundary angles was 0.33 degrees for the medium Goss grain of 1050 mu m and 0.25 degrees for the large Goss grain of 2978 mu m. In contrast, the average misorientation angles of the sub-boundaries after the final stage of secondary recrystallization were only 0.05 degrees. The results indicate that the sub-boundary angle is a determining parameter for the size of abnormally growing grains.

Automated summary

The size of sub-boundary angles affects the selective abnormal grain growth of Goss-oriented grains, with smaller sub-boundary energies resulting in larger grains. Measurements of subboundary angles for different sizes of Goss grains confirmed that the sub-boundary angle is a determining parameter for the size of abnormally growing grains.