Hardness of Al-based quasicrystals evaluated via cluster-plus-glue-atom model

Abstract

In this paper, the hardness of ternary Al-based quasicrystals was assessed through an application of the cluster-plus-glue-atom model. In this model, any structure is decomposed into a first-neighbour strongly bonded cluster part and second-neighbour weakly bonded glue-atom part so that the overall structural information is condensed into a local structural unit [cluster](glue atom)_x. For quasicrystals, the averaged local units are formulated as [icosahedron] TM_0,1(Transition Metal) and could be visualized as single icosahedron packing. Then, the hardness of quasicrystals was related to the rupture of weak inter-cluster bonds. Typically, theoretical hardness values of 8–9 GPa were obtained using 19 broken inter-cluster bonds, which accounts for about half of all the surface bonds of an icosahedron in the Mackay-type environment. The unit cluster formulas would act as rigid units during deformation and cracking.

Keywords:

• quasicrystals
• cluster-plus-glue-atom model
• hardness

Funding

This work was supported by the Natural Science Foundation of China under [grant number 51131002].