强流脉冲电子束作用下金属纯Cu的微观结构状态——变形结构

摘要

为了研究金属的超快变形机理,利用强流脉冲电子束（HCPEB）技术对多晶纯Cu进行了辐照处理,并利用透射电子显微镜对HCPEB诱发的表面微结构进行了表征.实验结果表明,HCPEB轰击多晶纯Cu后,在轰击表层诱发了幅值极大的应力和极高的应变速率.1次HCPEB轰击材料表层的变形结构以交滑移形成的位错胞和位错缠结结构为主;多次轰击后平行的位错墙和孪晶是该区域的主要变形结构特征;原子面的扩散乃至位错攀移可在晶界和孪晶界上形成台阶结构.根据各自区域的变形结构特征,对相应的变形机理进行了探讨.%In order to investigate the superfast deformation mechanism of metal,the high-current pulsed electron beam （HCPEB） technique is employed to irradiate the polycrystalline pure copper.The microstructure of the irradiated sublayer is investigated by using transmission electron microscopy.It is suggested that the stress with very high value and strain rate is introduced within the sublayer after HCPEB irradiation.The dislocation cell and the tangle dislocation formed by cross slip are the dominant defects after one-pulse HCPEB irradiation,whereas,dense dislocation walls and twins are the central microstructures after five-and ten-pulse irradiation.The diffusion and the climb of the atomic plane can cause the formation of the steps at the grain boundary and （or） the twin boundary.Based on the structure characteristics of the irradiated surface,the possible deformation mechanism induced by HCPEB irradiation is discussed.