Interfaces in quasicrystalline systems

摘要

Structural relations between quasicrystalline and related crystalline rational approximant phases have been of interest for some time now.Such relations are now being used to understand interface structures.Interfaces between structural motif-wise related,but dissimilarly periodic phases are expected to show a degree of lattice match in certain directions.Our earlier studies in the Al-Cu-Fe system using the HREM technique has shown this to be true.the strucutrla difference leads to well defined structural ledges in the interface between the icosahedral Al-Cu-Fe phase and the monoclinic Al_13Fe_4 type phase.In the present paper we report our results on the HREM study of interfaces in Al-Cu-Fe and Al-Pd-Mn systems.the emphasis will be on heterophase interfaces between quasiperiodic and periodic phases,where the two are strucutrally related.An attempt will be amde to correlate the results with calculated lattice projections of the two structures on the grain boundary plane.