贝氏体铁素体高分辨像

High Resolution Image of Bainitic Ferrite

用TEM和HRTEM观察分析了贝氏体钢中贝氏体铁素体组织的精细结构和高分辨像。确定了多元微合金空冷贝氏体钢中贝氏体铁素体组织为细小弥散分布，且形状多样。其超亚单元尺度仅几个纳米。贝氏体铁素体条束由多个亚片条组成。HRTEM像显示最小亚片条宽度仅几个纳米，多个亚片条宽度平均值约为7．0nm。观察结果显示，贝氏体铁素体亚片条间呈现小角度晶界排列，两亚片条间的界面并不光滑，存在台阶，其高度仅几个纳米，亚片条间界面有断续排列的原子无序区，宽度1～2nm，长度2～3nm。贝氏体铁素体n与残余奥氏体γ’HRTEM像显示，两者存在K—s取向关系。FFT图像变换显示出的原子图像更为清晰。a区有刃型位错存在，α／γ’界面有几个至十几个无序区原子层，尺寸为2～3nm，在γ’区也发现有原子排列不规则区。

The fine structure and high resolution images were observed and analyzed with TEM and HRTEM. The results show that the determined bainitic ferritic structure of multicomponent microalloyed air cooling bainitic steel is fine, dispersive distribution and variety appearance. The size of supperunite is several nanometers. A bainitic ferritic lath consists from several subplates. The HRTEM images reveal that minimum subplate is several nanome- ters, and their average width is 7.0 nm. The observation resules show that subplates of bainitic ferrite emerge as a small angle grain boundary arrangement. The interface between superplates in not leveling, and there are ledges, and its altitude is only several nanometers. We also found ledges. There are some discontinuous arrangement atom- ic disorder regions in interface of subplates. Their widths are about 1--2 nm, and lengths are 2--3 nm. The HR- TEM images between bainitic ferrite a and retained austenite γ display a K-S orientation relationship, and at same time FFT images were finished, so that the atomic images observed are more distinct. There are ledge-dislocations in α region. There are disorder atomic layers about 2--3 nm in α/γ interface and atomic arrangement disorder re- gions were also discoved in γregion.