ON THE FORMATION OF VACANCY TYPE DISLOCATION LOOPS FROM DISPLACEMENT CASCADES IN NICKEL
ON THE FORMATION OF VACANCY TYPE DISLOCATION LOOPS FROM DISPLACEMENT CASCADES IN NICKEL
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DOI：
10.1080/01418619108204851
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发表时间：
1991-02-01
期刊：
影响因子：
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通讯作者：
JENKINS, ML
中科院分区：
文献类型：
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作者：
ROBERTSON, IM;VETRANO, JS;JENKINS, ML
本文研究了50keVKr+、50keVNi+和100keVNi+重离子辐照镍的损伤结构随辐照温度(30和300K)和离子剂量(10(15)-10(17)离子m-2)的变化。辐射和电子显微镜都是在阿贡国家实验室的HVEM加速器设施中进行的。根据环路密度、环路大小和Burgers矢量分布来表征辐射的影响。在室温和30K下，孤立的位错级联都形成了位错环，但在30K时，位错环的形成几率要低得多，当30K辐照到室温时，会出现额外的位错环。在两种辐照温度下，缺陷产生率均随离子剂量的增加而降低。在连续辐照过程中，观察到孤立的位移级联形成了新的环，一些原有的环消失了，移动了与相邻环合并的位置。这些效应可以用分子动态计算机模拟模型来解释，该模型显示了置换级联中的“局部熔化”。随着离子剂量的增加，缺陷产生率下降归因于现有回路的合并以及当新的级联与现有回路在空间上重叠时发生的回路湮灭/重塑。
The damage structures produced in Ni by heavy-ion irradiations with 50 keV Kr+ and 50 and 100 keV Ni+ ions have been studied as a function of irradiation temperature (30 and 300 K) and ion dose (10(15)-10(17) ions m-2). Both irradiations and electron microscopy were performed in the HVEM-Accelerator facility at Argonne National Laboratory. The effects of the irradiations were characterized in terms of the loop densities, loop sizes and the Burgers vector distribution. Dislocation loops were formed from isolated displacement cascades both at room temperature and 30 K, although the loop formation probability was significantly lower at 30 K. Additional loops appeared when specimens irradiated at 30 K were warmed to room temperature. At both irradiation temperatures the defect production rate decreased with increasing ion dose. During continued irradiation it was observed that new loops formed from isolated displacement cascades, and some pre-existing loops disappeared, shifted position of coalesced with a neighbouring loop. These effects can be explained in terms of the molecular dynamic computer simulation model that displays 'local melting' within the displacement cascade. The decreasing defect production rate with increasing ion dose is attributed to the coalescence of existing loops and the annihilation/reformation of loops that occurs when a fresh cascade spatially overlaps with the existing loops.