High Resolution Electron-Microscope Study of Damage Evolution Processes in Metals and Their Alloys Irradiated with High Energy Particles

本工作发展了低温离子和中子辐照电镜的低温转移技术。本文根据离子、裂变中子和聚变中子辐照金属的低温冷转移透射电镜实验结果，揭示了高能粒子辐照金属损伤级联的形成和演化过程。(1)当初始Snock-on原子在金属中产生时，它与其它晶格原子碰撞后停止，形成中心部分被高浓度空位占据并被间隙地幔包围的位移损伤级联。以前认为空位聚集形成TEM可见的团簇（即，e.级联崩溃）和有害物质逃逸到附近的汇。在本工作中，发现空位形成亚电子显微镜尺寸的团簇，这些团簇在TEM下是不可见的，而杂质形成TEM可见团簇。(2)这是 ...更多信息 澄清了亚EM尺寸的空位和填隙型团簇与可见缺陷一起形成。(3)随着注量的增加，TEM不可见团簇有向TEM可见团簇转变的趋势。这是由于晶格弛豫的援助，从新的级联附近形成的先前形成的发射能量。这种效应被当代科学家命名为“级联能量叠加”。我们认为，这种效应是由于在新形成的叶栅上发射的激波造成的。详细的机理目前正在用超级计算机进行分子动力学模拟研究。(4)间隙原子强烈地向级联芯外发射，形成TEM可见的团簇。当与替换碰撞序列的距离相比时，发现该距离相当大。我们认为间隙原子是通过冲击波的表面机制输运的。这可能是为什么许多间隙点缺陷形成在集中的地方（即，e.分组）。对高温辐照下金属损伤形成的点缺陷过程，特别是损伤结构的演变和空洞的形成进行了广泛的研究。少

In the present work, we developed the cryotransfer technique of electron microscopy of ion- and neutron-irradiated at low temperature. From the experimental results of cryotransfer TEM of ion-, fission-neutron- and fusion-neutron-irradiated metals at low temperature, the following processes are decleared for the formation and evolution of damage cascades in high energy particle-irradiated metals. (1) When the primary snock-on atom is generated in metals, it stops after the collision with other lattice atoms and forms the displacement damage cascade whose the central part is occupied by high concentration of vacancies and is surrounded by the interstitial mantle. Previously it was believed that vacancies agglomerate to form TEM visible clusters (i. e. cascade collapse) and interstitials escapes to nearby sinks. In the present work, it was found that vacancies form sub-electron microscope size of clusters which are invisible by TEM while interstitials form TEM visible clusters. (2) It wa … More s clarified that sub-EM sizes of clusters of both vacancy and interstitial type were formed together with visible defects. (3) With increasing the fluence, TEM-invisible clusters tend to change to TEM visible clusters. This occurs due to the assistance of lattice relaxation by emitted energies from new cascades formed nearby previously formed ones. This effect is named by the present scientists "cascade energy overlapping". We believe that this effect is due to the shock-wave emitted at new formed cascade. The details of mechanism is at present studying by molecular-dynamical simulation with super-computer.(4) Interstitial atoms are emitted intensely towards the outside of cascade core and form TEM visible clusters. The distance was found to be fairly larger when it was compared with that due to the replacement collision sequence. We are proposing that an interstitial atom is transported by surfriding mechanism on the shock wave generated. This may be a reason why many interstitial dot defects form at concentrated place (i. e. groupings). These point defect processes of the formation of damages in metals which are irradiated at high temperature was examined extensively especially for the damage structure evolution and void formation. Less