Study of dynamical behavior of point defect clusters in neutron-irradiated metals at elevated temperature by electron microscopy

3年来，科研资助基金共发表了7篇论文(1)白银地区sigma-5边界附近位移损伤形成的计算机模拟研究。(2)高温中子辐照FCC金属位错附近间隙团簇的偏析。(3)中子辐照FCC金属中熔点缺陷吸收位错吸收效率在高温下的变化。(4)高温下中子辐照FCC金属位错增殖机理。(5)中子辐照FCC金属层错四面体（sft）和空穴在高温下成核和生长的原子机制。(6)高温下裂变中子辐照FCC金属损伤结构演化的原子机制。(7) 14mev中子辐照FCC金属D-T聚变损伤结构演化的原子机制。在这些工作中，最重要的结果是中子辐照FCC金属在高温下形成空位团簇和sft的原子机制。透射电镜观察表明，在催化裂化金属中，两种空穴和瞬变同时形成。一个空缺中包含的空缺数大于500个，而一个sft中的空缺数小于250个。计算机模拟表明，空位团簇在结构松弛为弦状团簇后，可以通过大马士革- diene - weizer弛豫作为团簇运动。当v簇中的空位数小于250时，簇松弛为1个sft。sft是Cu和Ni中最稳定的结构。当簇中的空位数超过500个时，由于各向异性，它不会松弛为1（111）个血小板。团簇松弛成球形，由大量的{111}v型血小板组成。它的球状星团最终松弛成一个空洞。

Following seven items were published during 3 years supports of GRAND-IN-AID FOR SCIENTIFIC RESEARCH (1) A computer simulation study on displacement damage formation near sigma-5 boundary in Silver. (2) Segregation of interstitial clusters near dislocations in FCC metals neutron-irradiated at high temperature. (3) Changes of the dislocation sink efficiency of point defect absorption for the fluence in neutron-irradiated FCC metals at high temperature. (4) Multiplication mechanism of dislocations in neutron-irradiated FCC metals at high temperature. (5) Atomistic mechanism of nucleation and growth of stacking fault tetrahedra (sft) and voids in neutron-irradiated FCC metals at high temperature. (6) Atomistic mechanism of damage structure evolution in fission neutron irradiated FCC metals at high temperature. (7) Atomistic mechanism of damage structure evolution in D-T fusion 14 MeV neutron irradiated FCC metals. In these works, the most significant result is the atomistic mechanism of the formation of vacancy clusters of voids and sft in neutron-irradiated FCC metals at high temperature. TEM observations showed that both of voids and sft form in an FCC metal simultaneously. The number of vacancy that is contained in a void is more than 500, while the number of vacancy in an sft is less than 250. Computer simulation shows that vacancy clusters can move as a cluster through Damask-Dienes-Weizer relaxation after the structure relaxes to string-like cluster. When a number of vacancies in a v-cluster are less than 250, the cluster relaxes to an sft. The sft is the most stable structure in Cu and Ni. When a number of vacancies in a cluster are more than 500, it does not relax to a one (111) platelet due to an anisotropy. A cluster relaxes to a spherical configuration, which are composed by a large number of {111} v-platelets. Its spherical clusters finally relax to a void.