ON THE ENERGY RATIO BETWEEN THE PHONON AND THE PHASON PART OF DISLOCATIONS IN ICOSAHEDRAL AL-PD-MN QUASI-CRYSTALS

Using two different ansatze for the energy of quasicrystal dislocation s the phonon strain energy is related to the phason strain energy by m eans of the strain energy ratio. The possible ranges for this ratio ar e determined while a new type of dislocation dissociation is proposed. This reaction describes the dissociation of a perfect dislocation int o two other also perfect dislocations. Based on recent experimental ob servations the energy ratio due to phason and phonon strain of disloca tions with Burgers vectors along twofold directions is calculated. Als o recent experimental observations of partial dislocations are conside red. Implications for the mechanisms stabilizing the quasicrystalline structures are discussed.