Al-Ni-Rh复杂合金相中特殊面缺陷的电子显微学研究

On electron microscopy study of special planar defects in Al-Ni-Rh complex alloys

利用高分辨透射电子显微学方法,研究了复杂合金相ξ-′Al-Ni-Rh和-ξAl-Ni-Rh相中一种特殊类型面缺陷。这种面缺陷的晶体学特点是,其结构特征不仅涉及描述通常晶体中面缺陷的平移矢量,而且还涉及原子团簇之间的位置交换。而后者通常出现在不具平移周期性的准晶中,称为相子缺陷。研究表明,这种特殊的面缺陷不仅呈现随机分布状态,也可周期性排列形成新的大晶胞调制结构。此外,本文还将报道与这种特殊面缺陷相关的晶界、畴界、孪晶、层错等面缺陷的研究。

Special planar defects in ξ-′Al-Ni-Rh and -ξAl-Ni-Rh phases with complex structure were studied by transmission electron microscopy. The main characteristics of the planar defects are related with both of the displacement vectors of the normal crystals and a special kind of flips of atom clusters. These flips are unique character in quasi-crystals and termed as phasons. Our experimental results indicate that the special planar defects can exist either randomly in some domains, or a kind of modulated structure with large unit cell by periodic arrangement of these planar defects in other domains. In addition, we shown also the structural relationship between the special planar defects and other types of planar defects, such as, grain boundaries, domain boundaries, and twin boundaries.