TEM analysis for meso-scale textures developed in heavily deformed Fe-alloys

用透射电镜研究了冷轧310 S钢中的细晶组织。310 S的变形组织特征是发展致密的T-M层状组织并形成剪切带。在70%的减薄应变下，在T-M层流区观察到了包括高度取向差的亚微米级晶粒的剪切带。剪切带中的晶粒被拉长，其尺寸一般大于T-M片层间距。尽管剪切带中的晶体取向分布很广，但它们的分散倾向于发生在T-M层片中基体和孪晶区的晶体取向之间。从结构的纵截面中获得的选定区域衍射图案表现出大的结晶取向的散射，在SB中也观察到这种趋势。TEM观察也在横截面，以检查这些微观结构的3-D方面。在此基础上，讨论了剪切带中细晶组织的形成过程及晶界在细晶组织形成中的作用，并利用透射电镜观察了冷轧Fe-Si合金晶体中的变形组织。采用{111 C}<112>和{001}<110>晶向，观察到两种晶向的位错结构。在{1 I1}晶体中<112>，形成了高密度的片层结构，并形成了剪切带，而在{001}晶体中<110>，虽然位错密度相对于{111}取向的晶体来说较低，但仍观察到位错胞结构<112>。

Fine-grained structures evolved in cold-rolled 310S steels has been investigated by using transmission electron microscopy. Deformation microstructures in 310S is characterized by the development of dense T-M lamellae and the following formation of shear bands. At the strain of 70 % thickness reduction, shear bands including highly misoriented submicron-sized grains were observed in the region with T-M lamellae. The grains in shear bands were somewhat elongated, and their size was generally larger than the T-M lamella spacing. Although crystal orientations in shear bands widely spread, their scattering tends to occur between the crystal orientations of matrix and twinning regions in the T-M lamellae.In addition to those microstructures, we have found a characteristic fine-grained structure newly formed around initial grain boundaries. Selected area diffraction patterns obtained from the structure in the longitudinal section exhibited a large scattering of crystallographic orientation, the tendency of which was also observed in SBs. TEM observations were made also in the transverse section in order to examine 3-D aspects of those microstructures. On the basis of results, formation process of fine-grained microstructure in shear bands and the effect of grain boundaries in the formation of fine-grained structures is discussed.Next, deformation micro-structures developed in cold-rolled Fe-Si alloy crystals have been examined by using transmission electron microscopy. Crystals orientations of {111C}<112> and {001}<110> were employed, and the dislocation structures in crystals with the both orientations have been observed. In {1I1}<112> crystals, high density of lamellar structure was developed, and the formation of shear bands were found. In {001}<110> crystals, on the other hand, dislocation cell structure was observed, though the dislocation density was relatively low comparing the crystals with the orientation of {111}<112>.