中文摘要：

钒合金作为聚变堆候选材料,其辐照损伤行为一直是关注的重点.研究辐照时形成的位错环的性质,其意义在于揭示纯钒中辐照空洞的长大机理.这种机理表现为不同类型位错环对点缺陷吸收的偏压不同,从而影响金属的辐照肿胀.本文利用加速器对纯钒薄膜样品进行氢离子辐照,然后,利用透射电镜的inside-outside方法分析氢离子辐照所形成的位错环的类型.结果表明,在氢离子辐照纯钒中没有发现柏氏矢量b=〈100〉的位错环,只有柏氏矢量b=1/2〈111〉和b=〈110〉的位错环,这两种位错环的惯性面处于110—112之间.能确定性质的位错环全部为间隙型位错环,未发现空位型位错环。

英文摘要：

Vanadium alloys are considered as the candidate materials for structure application in fusion reactors because of their low radiation-induced activation, high resistance to radiation damage, high thermal conduction, and low thermal expansion coefficient. Before these materials, which will be exposed to high-flux hydrogen and helium isotopes, may be safely used in fusion device much more data based on irradiation damage are required. The study of dislocation loops in vanadium is designed to indicate the mechanism of void growing under irradiation. The mechanism is that different types of dislocation loops have different bias which represent their abilities to absorb point defects. It is possible to explain the irradiation swelling performance in the material with the bias of loops. The thin disks samples used in this experiment are made of pure vanadium and vanadium alloy（V-4Cr-4Ti） by twin-jet electro-polishing. Electrolyte of H_2SO_4-CH_3OH（1 ： 6 by volume） at 20？C is used in a current of 80–120 m A. To get a clear view of dislocation loops,the SRIM code is used to simulate the implantation of hydrogen ions into vanadium. The ion irradiation is carried out to a dose of 5 1016H＋/cm-2, at an energy of 30 keV. Microstructure observations are performed on a Tecnai G2F20（transmission electron microscope, TEM） at an accelerating voltage of 200 kV. The Burger＇s vectors and nature of the dislocation loops formed in pure vanadium by hydrogen implantation are confirmed by TEM. This experiment has focused on as many as 76 dislocation loops, lots of images are taken under different diffraction conditions from the same areas of interest. Results show that most of the dislocation loops have a Burger＇s vectors of 1/2111（ 90%）, and a few of 110. No loops with b = 100 loops can be found in this study. The nature of dislocation loops is determined by the inside-outside method. The number of the dislocation loops that can make sure of their nature is 29, and all of them are conformed to be interstitial