HIGH-RESOLUTION ELECTRON-MICROSCOPY AND ATOMIC ARRANGEMENTS OF AL-MN-SI AND AL-LI-CU ICOSAHEDRAL QUASI-CRYSTALS

Two types of icosahedral quasicrystals of Al-Mn-Si and Al-Li-Cu were examined with a 400 kV high-resolution electron microscope having a resolution of 0.17 nm. Their images taken with the incident beam parallel to the fivefold symmetry axis clearly show a structure model formed by the aggregation of atom clusters with icosahedral symmetry. The observed image contrast of Al-Mn-Si was reproduced by an image calculation of the structure model using the multislice method. The calculation demonstrated that high-resolution images taken with the 400 kV electron microscope faithfully represent projected potential of the quasicrystals. © 1990, The Japan Institute of Metals. All rights reserved.