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

用透射电子显微镜研究了冷轧310S钢的细晶组织演变。310S的变形组织以致密的T-M片层和随后形成的剪切带为特征。在70%的减厚应变下，在T-M片层区域观察到含有高度错位取向的亚微米级晶粒的剪切带。剪切带中的颗粒略有拉长，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，但它们的散射往往发生在T-M片层中母体区和孪晶区的晶体取向之间。除了这些微观组织外，我们还发现在初始晶界周围形成了一种新的特征细晶结构。从纵向结构得到的选区衍射图显示出很大的晶体取向散射，在SBS中也观察到了这一趋势。在横切面上也进行了电子显微镜观察，以检查这些微观结构的3-D方面。在此基础上，讨论了剪切带细晶组织的形成过程以及晶界在细晶组织形成过程中的作用。其次，用透射电子显微镜观察了冷轧Fe-Si合金晶体的形变组织。采用了{111C}&lt；112&gt；和{001}&lt；110&gt；的晶体取向，观察到了这两种取向的晶体中的位错结构。在{1I1}&lt；112&gt；晶体中，形成了高密度的片层结构，并形成了剪切带。而在{001}&lt；110&gt；晶体中，虽然位错密度相对较低，但在{111}&lt；112&gt；晶体中观察到了位错胞结构。

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>.