Stacking-fault contrast was studied, by means of transmission electron microscopy, in high-temperature plastically deformed icosahedral quasi-crystals. Bright-field and dark-field contrast and trace analyses showed that there were 2 types of stacking fault contrast. One involved a fault plane which was perpendicular to a 2-fold axis, and a displacement vector which was parallel to the fault plane normal. The other involved a fault plane which was perpendicular to a 5-fold axis, and a displacement vector which was parallel to the fault plane normal. High-resolution electron microscopy revealed that these stacking fault contrasts were not due to conventional planar defects. They were found to be broadened so as to form wavy bounded stacking-fault platelets of about 2.5 to 10nm in thickness. The stacking-fault contrasts for samples which had been subjected to deformation under various conditions were consistent with the suggestion that moving dislocations in quasi-crystalline materials left phason-type stacking faults behind which then broadened and disappeared due to the enhanced diffusion at high temperatures.

Stacking Faults in High-Temperature Deformed Al-Pd-Mn Icosahedral Quasi-Crystals R.Wang, M.Feuerbacher, W.Yang, K.Urban: Philosophical Magazine A, 1998, 78[2], 273-84