Heterogeneous nucleation of icosahedral phase from FCC phase in cast Al87Mn4Si2Be7 alloy

Abstract

The formation of the icosahedral (i) quasicrystalline phase has been studied in the cast Al87Mn4Si2Be7 alloy. Under low cooling rates, i-phase particles of about 5 to 15 mm formed in the alpha(A1) matrix. A thorough examination of the microstructure revealed the existence of cubic crystalline phases embedded in the i-particles. Microstructural and thermal analyses indicated that the i-particles nucleated heterogeneously from the cubic AlMn(Si)Be-4 phases by a peritectic reaction, however with a slight misorientation.