Peculiarities in contact interaction of crystalline and quasicrystalline phases with molten metals

Abstract

The contact interaction of quasicrystalline and crystalline phases of Al—Co— Cu and Al—Co—Ni alloys with copper- or aluminum-based melts was analyzed in this work. The lower dissolution rate of the quasicrystalline decagonal phase as compared to that of crystalline one is explained considering the formality of high anisotropic crystals theory. The expressions for free energy, entropy, internal energy, and heat capacity of the quasicrystalline and the crystalline phases are obtained based on the Debye model. The slower dissolution of the quasicrystalline phase relates to the reduction of an average geometric vibration frequency of its atoms due to the distribution of excess energy of the quasicrystals among the larger quantity of freedom degrees.