| As a high magnetic induction material,Hi-B steel is widely used in electric power,electrical and other fields.The abnormal growth behavior of Goss-oriented grains has been valued.The researchers found that some island grains would be left behind in the Goss grain during the high temperature annealing.The traditional method is based on the observation of the single two-dimensional plane of the sample to analyze the microstructure characteristics of Hi-B steel.In this paper,continuous slicing,computer-aided reconstruction and visualization,and electron backscatter diffraction techniques is used to characterize the three-dimensional morphology of island grains in Hi-B steel,and to study the formation mechanism of island grains.The research shows:(1)Goss-oriented grains grow abnormally at 1040°C and the grain size is bimodal distribution.The front edge of the grain boundary shows an inhomogeneous serrated shape,where part of the grain is inserted into the adjacent two grains,which is similar to the shape of tentacles.(2)In the process of abnormal growth of Goss-oriented grains,there are several ways to form island grains: Brass grains obstruct the consumption of Goss-oriented grains due to similar characteristics with Goss-oriented grains;The over-sized grains hinders the ingestion of Goss-oriented grains;Goss-oriented grains bypass or invade adjacent grains between adjacent grains and gradually wrap those grains because of Goss-oriented grains at high mobility at the HE grain boundary or solid wettability.(3)The three-dimensional morphology of the island grains mainly presents an inverted cone with a larger upper size and smaller lower size.Both the brass orientation and the larger size of the island grains in the RD direction are larger than those in the TD and ND directions,while the size of the passively wrapped island grains is not much different form those in the three directions. |
PDF Full Text Request