Molecular ion irradiations of molybdenum
Molecular ion irradiations of molybdenum
复制标题
DOI：
10.1080/14786430903217826
复制
发表时间：
2010-01
影响因子：
1.6
通讯作者：
C. English;M. Jenkins
中科院分区：
文献类型：
--
作者：
C. English;M. Jenkins
通过一系列透射电镜实验，系统地研究了钼中位错级联中空位位错环的形成。用Sb+单离子和分子离子对高纯钼单晶箔进行低剂量（≤1016离子m−2）辐照。采用三种不同的离子能量（60，120和180千电子伏），以系统地改变总级联能量和分子离子中每个原子的能量。位错环的大小和缺陷产率被发现是较大的分子离子比相同能量的单离子。在（011）箔中，大多数回路的伯格斯矢量B = a/2 111位于箔的平面内。然而，在分子离子辐照中，也发现了一小部分B = a ~ 100 μ m的环，这一部分比离子辐照高，并且随着离子能量的增加而增加。在（001）箔中，由于表面上的滑移α/2 π 111 π环的损失，缺陷产额要小得多，但在分子离子辐照中仍然存在π 100 π环。α/2 π 111 π和α π 100 π环的惯习面均符合Eyre-Bullough机制在{110}面上的成核。这些结果进行了比较，最近的分子动力学模拟的质量上的位移级联在铁的初级撞击原子的效果。
A series of TEM experiments was carried out to systematically investigate the formation of vacancy dislocation loops in displacement cascades in molybdenum. Single-crystal foils of high-purity molybdenum were irradiated with Sb+ single ions and and molecular ions to low doses (≤1016 ions m−2). Three different ion energies were employed (60, l20 and 180 keV) in order to systematically vary the total cascade energy and the energy per atom in the molecular ion. Dislocation loop sizes and defect yields were found to be larger for molecular ions than for single ions of the same energy. In (011) foils, most loops had Burgers vectors b = a/2⟨111⟩ lying in the plane of the foil. However, in molecular ion irradiations, a small fraction of loops with b = a⟨100⟩ was also found. This fraction was higher for than for ions and also increased with ion energy. In (001) foils, defect yields were much smaller because of the loss of glissile a/2⟨111⟩ loops to the surface, but a⟨100⟩ loops were still present in molecular ion irradiations. The habit planes of both a/2⟨111⟩ and a⟨100⟩ loops were consistent with nucleation on {110} planes by the Eyre–Bullough mechanism. These results are compared with recent molecular dynamics simulations of the effect of the mass of primary knock-on atoms on displacement cascades in iron.