LATTICE TRANSFORMATIONS IN THE APPROXIMANT AND DECAGONAL PHASES

A few two-dimensional approximant-approximant and approximant-quasicrystal lattice transformations are studied. These lattice transformations are governed by three mechanisms: translational slip, rotational slip and irrational twinning. These operations can generate an infinite number of approximants, most of them having commensurate structure. The irrational twinning generates either the one-dimensional or two-dimensional aperiodic lattices depending on the orientation of the irrational twin plane with respect to the periodic lattice. Experimental evidence in favour of such lattice transformations is supplied by high-resolution electron microscopy imaging in two approximant structures.