中文摘要：

采用Hopkinson压杆冲击加载装置和帽形试样对电工纯铁进行约10^3s^-1应变率条件下的冲击压缩实验，利用光学显微镜、扫描电镜和透射电镜观察高速冲击后电工纯铁剪切带及微观组织．结果表明，电工纯铁中的剪切带（ASB）由带中心比较平滑、细小晶粒和带边缘被拉长的变形晶粒（过渡区）组成．过渡区中晶粒有一定择优取向，衍射花样分别为不连续椭圆状和环状．剪切带中心晶粒直径小于0．5μm，锻态和轧制态电工纯铁ASB中心衍射花样分别为不连续和连续环状．ASB内位错密度很低，但其相邻基体内含有高密度位错．ASB内没有相变发生．

英文摘要：

Microstructural evolution of adiabatic shear bands （ASB） in DT4 has been investigated. Tests were performed using a specially designed stepped specimen and Hopkinson bar. The results showed that the fracture surface of the shear band was characterized by （1） regions of elongated dimples within which no second phase particles were observed, and （2） regions with a relatively flat and smeared appearance. The granula in the region between the center of adiabatic shear band and matrix exhibited some preferred orientation. Electron diffraction patterns appear as some discontinuous ellipses and rings within the regions of elongated dimples in the forged electro iron and rolled electro iron respectively. The dislocation is very low in the ASB. At the same time, high dislocations were found in microstructure of adjacent matrices. Microgranules in center of shear band in DT4 was symmetrical with an average diameter less than 0.5μm.