COMPUTER EXPERIMENTS OF FRACTURE OF 2-DIMENSIONAL HENLEY-ELSER TYPE QUASI-CRYSTALS

Fracture processes in two-dimensional Henley-Elser type quasicrystals were studied by the molecular dynamics method (MD). The model structur es were ternary systems and were prerelaxed for the subsequent deforma tion process. The deformation process was simulated by structural rela xation by MD while the calculation cell was extended along a uniaxial direction by a certain factor after a certain time interval. The syste m temperature was kept constant by the scaling method during the calcu lation. The system temperature and potential energy were monitored to detect microscopic bond breaking in the sample. We found a large varia nce in the change in potential energy when the deformation process mov ed into plasticity from elasticity, corresponding to the creation of v oids in the specimen. By changing the strength of the model potential, different types of deformation process were observed. The stability o f the pentagonal clusters, which are considered to be the unit structu re of the quasicrystal, was changed drastically according to the stren gth of the heterogeneous interaction in the pentagonal cluster. Conseq uently, different types of fracture, i.e. interpentagonal and intrapen tagonal cluster, occurred depending on the strength of the heterogeneo us interaction.