Abstract
Transmission electron microscopy (TEM) observations on Cd-based 2/1 cubic approximants and quasicrystals were performed at low temperatures down to 20 K. For 2/1 approximants, the appearance of superlattice spots was commonly observed at temperatures below 110 K, suggesting the occurrence of a phase transition. For quasicrystals, no appreciable change in diffraction pattern was recognized at temperatures down to 20 K, which may suggest that no phase transition occurred.