论文部分内容阅读
纳米材料的性能不仅与纳米晶粒本身的结构有关,而且与纳米晶体之间界面的微观结构有关.纳米粉在压实成纳米块过程中很难消除微孔洞,并且在压实过程中也会给晶粒引入结构缺陷.本文用正电子湮没谱学研究了纳米Cu固体材料微结构,发现在两种不同条件下压制成型的纳米Cu固体内部的晶粒界面均存在着单空位及空位团等缺陷.空位团的大小随着压制压力的增加而略有减小.通过退火实验发现纳米Cu固体的界面缺陷具有较好的热稳定性.即使在900℃高温下退火也只能使部分缺陷得到恢复,但是低压力下压制的样品中的缺陷恢复需要更高的温度.
The properties of nanomaterials are not only related to the structure of the nanocrystal itself, but also related to the microstructure of the interface between the nanocrystals, which are difficult to eliminate in the process of compaction into nanoblocks, Will introduce structural defects into the grains.In this paper, the positron annihilation spectroscopy was used to study the microstructures of nano-Cu solid materials and it was found that there existed single vacancy and vacancy groups in the grain boundaries of nano-Cu solid pressed under two different conditions Etc. The size of vacancy groups decreases slightly with the increase of pressing pressure.The nanocomposite Cu nanocrystal interface defects have good thermal stability by annealing experiment.Even annealing at high temperature of 900 ℃ can only make partial defects Recovered, but the defect recovery in samples pressed at low pressure required higher temperatures.