Electron Microscope Observation of Friauf-Laves Phase Mg(Cu1−xAlx)2 with x=0.465
1977 年 18 巻 1 号 p. 39-45
詳細
1977 年 18 巻 1 号 p. 39-45
Electron microscope observation was made on a Mg-base Friauf-Laves phase Mg(Cu1−xAlx)2 with x=0.465. As-cast specimens exhibited mainly a 4-layer type structure, and annealed ones a 9-layer type. In addition, small regions with other layer types such as 2-, 6-, 10- and 16-layer types were also observed. Two new stacking variants having 6- and 16-layer type structures were analysed by comparing diffracted intensities with calculated ones. The 6-layer type structure is expressed as ABC′B′AB′ in terms of the six compound layers of the Friauf-Laves phase. The space group is P\bar6m2 with a unit cell of dimensions a=5.10 and c=25.0 Å. The 16-layer type structure is expressed as ABC′BCA′CAB′A′CA′C′BC′B′ having a space group P63/mmc with lattice constants a=5.10 and c=66.7 Å.
The lattice images of the 2-, 4-, 6-, 9-, 10- and 16-layer type structure were obtained by using a direct beam and several reflected beams. A remarkable correspondence was found between the lattice image and the layer sequence.
