Research Of Microstructure And Three-dimensional Grain Morphology Of Secondary Recrystallization In Hi-B Steel

For a long time,the microstructure of the material was observed and analyzed by two dimensional images which can not accurately characterize the microstructure.In this paper,evolution of microstructure during the secondary recrystallization annealing process of Hi-B steel were studied by EBSD technique,then combined with the continuous slice method and computer aided three-dimensional reconstruction.The three-dimensional morphology of different oriented grains was observed and analyzed during the secondary recrystallization process.The main results are as follows:(1)Under the conditions of the process,the Goss grains start to grow abnormally from 1060?to 1080?and the size of grains reached the millimeter level from 1100?to1120?.After the abnormal growth,Goss grains have the size advantage.Moreover,in this paper,secondary recrystallization of Hi-B steel was divided into the following three stages: the stage that grains grow normally,the stage that grains grow abnormally and the stage that grains grow up after contacting.At different stages,the growth mechanisms of Goss grains were different.(2)At the stage that grains grow normally,the three-dimensional morphology of each oriented grains was little different,emerged relatively regular column;At the stage that grains grows abnormally,the Goss grains showed bulging shape.In the middle part of the {111}<112> oriented grains and the {001}<110> oriented grains,the convex part was presented.Also,the {111}<112> oriented grains have a tendency to shrink themselves.At the same time,the three-dimensional morphology of Brass grains was tapered;At the stage that grains grow up after contacting,the bulging morphology of Goss grains is more obvious.The three-dimensional morphology of {111}<112>oriented grains and {001}<110> oriented grains had little change and the three-dimensional morphology of the Brass grains were still tapered,but the taper becomes larger.(3)The three-dimensional morphology of the island grain which was completelylocated inside the large grain showed a regular ellipsoid.The three-dimensional morphology of the island grain which was partially embedded in the large grain was conical.