Abstract:

Three-dimensional (3D) characterization of the microstructure containing exceptional big grains of industrial pure iron was carried out by means of serial sectioning, 3D reconstruction,and EBSD analysis. The differences between the exceptional big grains and the normal grains were analyzed in emphases. The dimensions of the 3D reconstructed pure iron sample are 1920 μm×1219 μm×720 μm, containing 12354 grains which includes5whole exceptional big ones. Different from previous reconstructed 3D grain microstructures without crystallographic orientation information,the present reconstructed 3Dgrains containsimultaneously both the geometric configuration information and the crystallographic orientation information of grains.The results show that the numbers of interfaces of the 5 exceptional big grains studied arein the range of 128-669 (i.e., the largest grain contacts simultaneously 669 neighboring grains). The average misorientation between the exceptional big grains and theirneighboring grains, and theirmisorientationwith their neighbors in the range of 40°-55°, are evidently higher than that between ordinary grains.

Key words: annealed pure iron, exceptional big grain, 3D geometric configuration, grain orientation, 3D reconstruction