Interface Studies in a Quasicrystalline Al – Pd – Mn Alloy

Characterisation of interfaces in quasicrystalline materials is of particular interest with respect OF to the known structural relations between the quasi crystalline phases and the co-existing crystalline phases. In the present paper, the status of experimental results on the structure of interfaces in quasicrystalline systems is reviewed. In addition, results of our experimental investigation of interfaces in Al - Pd - Mn system is reported. A co-existing crystalline phase is found that is structurally related to the icosahedral phase. In addition to the change in structure, composition and orientation, translational order also changes across an interface between the icosahedral and related crystalline phases. Ledges have been observed at interfaces where the interfacial plane is normal to the common symmetry axis shared by the two phases. The OF observed special features of grain boundaries and ledge interfaces are discussed in terms of common structural motifs and the resulting orientation relation between the quasicrystalline and related crystalline phases.