【作者】 周明哲；

【导师】 张喜燕；

【作者基本信息】 广西大学 ， 材料物理与化学， 2006， 硕士

【摘要】 对于纳米结构材料，由于晶粒尺寸的减小，其许多性质发生了重大的改变。许多研究表明了晶界作为纳米材料中大量存在的组成部分对其构成的影响，但对于纳米材料中晶粒的微结构研究仍比较少。本文根据前人的理论基础，计算了晶界对纳米材料中晶格畸变的影响，并据此提出了在纳米结构材料中存在分层结构的观点。根据计算表征了分层结构中内外两层晶粒的特征：其外层是晶格畸变量较大，且畸变量随着靠近晶界距离的减小而增大的过渡层；而内层是晶格畸变较小，且畸变量不随靠近晶界距离变化而发生变化的近似理想晶粒。 结合X射线衍射，论证了纳米材料中存在分层结构的合理性，并讨论了变形过程中其结构演变及缺陷形式。通过高分辨透射电镜观察到纳米金属钴的晶粒分层结构，从实验上给出分层结构的有力证据。更多还原

【Abstract】 As a result of the decreasing size of nanocrystalline, its character changed simultaneously. Most studies are focused on the influence of grain boundaries, which plays an important role in the in the nanocrystalline. But less concern on the microstructure of the grain. Based on the other’s theory, we calculate the influence of grain boundaries to the aberration of the crystal lattice. And conclude that there’re two layers in the nanocrystalline grain. In the outer layer, the aberration of the crystal lattice is larger than in the inner layer, the closer to the grain boundary, the lager aberration is. But in the inner layer, the relation is unobserved. The aberration in these area is neglectable. By the use of X-ray diffraction, we testified the rationality of the layer structure in the nanocrystalline grain, and discussed the evolvement of the microstructure and the form of the vacancy. The most important, we had observed the layer structure by using of HRTEM, it’s the most powerful evidence of the layer structure.更多还原