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

高能粒子辐照金属及其合金损伤演化过程的高分辨率电子显微镜研究

基本信息

批准号：
62420045
负责人：
SHIMOMURA Yoshiharu
金额：
$ 9.02万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1990
项目状态：
已结题

项目摘要

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

在本工作中，我们发展了低温离子和中子辐照电子显微镜的低温转移技术。根据离子、裂变中子和聚变中子辐照金属的低温低温转移电子显微镜实验结果，揭示了高能粒子辐照金属损伤级联的形成和演化过程。(1)当金属中产生初级Snock-on原子时，它在与其他晶格原子碰撞后停止，并形成位移损伤级联，其中心部分被高浓度的空位占据，并被间隙地幔包围。以前，人们认为空位聚集在一起，形成了透射电子显微镜可见的团簇(即级联坍塌)，间隙逃逸到附近的下沉。在本工作中，发现空位形成了透射电子显微镜下不可见的团簇的亚电子显微镜尺寸，而间隙形成了透射电子显微镜下可见的团簇。(2)It Wa…更多的S澄清说，亚EM尺寸的空位和间隙类型的团簇是与可见的缺陷一起形成的。(3)随着注量的增加，不可见团簇倾向于向可见团簇转变。这是由于在先前形成的级联附近形成的新级联发出的能量帮助了晶格弛豫。这种效应被目前的科学家命名为“级联能量重叠”。我们认为这种效应是由于新形成的叶栅所产生的激波所致。机理的细节目前还在用超级计算机进行分子动力学模拟研究。(4)间隙原子向级联核心外强烈发射，形成可见的电子显微镜团簇。当与替换碰撞序列的距离进行比较时，发现该距离相当大。我们提出间隙原子在产生的冲击波上是通过堆积机制输运的。这可能是为什么许多间质性网点缺陷形成在集中的地方(即分组)的一个原因。对高温辐照金属中损伤形成的这些点缺陷过程进行了广泛的研究，特别是损伤结构的演化和空洞的形成。较少