Synchrotron X-ray microdiffraction analysis of abnormally growing grains induced by indentation in Fe-3%Si steel

Abstract The effect of indentation using hardness testers on abnormal grain growth (AGG) of non-Goss grains were studied in Fe-3%Si steel. The primary recrystallized specimen was locally deformed by indentation under loads of 0.01, 0.05, 0.1, 0.2, 0.5, 2, 3, 6, 12 and 18 kgf and then heated to 860 °C and held for 10 min for recrystallization or recovery. When these specimens were heated to 1080 °C, AGG of non-Goss grains occurred around the area deformed by indentation loaded above 0.1 kgf. One abnormally growing grain was observed in the specimen indented under the loads of 0.2, 0.5, 2, 3 and 6 kgf, whereas three and eight abnormally growing grains were observed respectively in the specimen indented under loads of 12 and 18 kgf. Analyses by synchrotron X-ray microdiffraction show that all abnormally growing grains had sub-boundaries with the misorientation angles below 0.6o whereas no matrix grain had sub-boundaries.