纳米Cu固体材料的X射线衍射与正电子湮没研究
Investigation of nanocrystalline Cu by X-ray diffraction and positron annihilation
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摘要: 采用自悬浮-冷压法，在不同压力下制得纳米Cu固体材料并对其在不同温度和保温时间下进行退火，利用X射线衍射(XRD)和正电子湮没寿命谱(PAS)分析对材料的结构和微观缺陷进行了表征。XRD分析表明，压制而得的样品晶粒度为20 nm，低于300 ℃退火3 h后并未发现晶粒显著长大；PAS分析表明，压制后的样品缺陷主要为单空位和空位团，大空隙很少，随着退火温度的升高和退火时间的延长，单空位通过扩散结合成空位团，大空隙也在温度较高时分解为空位团，导致空位团的含量增加，而单空位和大空隙的含量降低。
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关键词:
- 自悬浮-冷压法 /
- 纳米Cu /
- X射线衍射(XRD) /
- 正电子湮没谱(PAS) /
- ICF靶材料
Abstract: The nanocrystalline Cu was prepared by flow-levitation-cold-pressing method under different pressures and then annealed at different temperatures with different annealing time. The X-ray diffraction (XRD) and positron annihilation spectroscopy (PAS) were used to determine the structure and microdefects in the nanocrystallie Cu. The XRD analysis results show that the grain size of the specimen after being pressed is 20 nm and does not grow prominently after annealing below 300℃ for 3 h. The PAS analysis results show that most of the defects in the specimen after press is vacancies and vacancy-clusters, the amount of micro-voids is small; after being annealed at high temperature or for a long time, the vacancies aggregate together to form vacancy-cluster by diffusion, the micro-voids break -
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