强流脉冲电子束作用下纯镍表层中织构及结构缺陷的演化行为

利用强流脉冲电子束(HCPEB)装置对金属纯Ni进行轰击,采用X射线衍射及透射电子显微镜(TEM)技术详细分析了受轰击样品的变形结构和缺陷。X射线衍射分析表明,经强流脉冲电子束处理后,在{111}和{200}晶面出现了择优取向。TEM表层微观结构分析表明:强流脉冲电子束轰击1次和5次后,晶粒内部形成了大量的(111)112]型波状条带结构,在波状条带内部包含大量平行的(200)110]型微条带;10次轰击后,样品变形结构发生变化,除大量的条带状结构外,变形孪晶的数量明显增多。这些变形微结构不仅影响表层的织构演化行为,而且还能细化晶粒,强流脉冲电子束技术为制备表面纳米材料提供了一条有效的途径。

Texture and Structural Defect Evolution of Pure Nickel Subjected to High-Current Pulse Electron Beam Irradiation

The specimens of polycrystalline nickel were irradiated with high-current pulsed electron beam (HCPEB). Surface textures and structural defects of irradiated nickel were investigated by using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD results show that the characteristics of preferential orientation {111} and {200} are presented after HCPEB treatments. While the treating pulses were chosen as 1 and 5 times, the surface microstructure changes after irradiation was analyzed by TEM. Within the surface layer the (111) 112] type of wave shear bands are formed in the interior of grains. Large numbers of (200) 110] types of micro-bands parallel each other embed in the wave bands. After 10 pulses, the deformation structure changed prominently. Besides the wave bands, the number of deformation twins increase evidently. The formation of these deformation structures has a significant effect both on the evolution of surface textures and grains refinement. It is suggested that HCPEB technique is becoming an effective approach to fabricate surface nanocrystalline materials.