The microstructure of the Al-Mn(-Cu)-Be-Si alloys analyzed by X-ray diffraction and TEM consisted of icosahedral (i) quasicrystal particles embedded in alpha(A1) matrix. The conjoint addition of Si and Be elements enabled the i-phase formation in circle divide 10 mm specimens prepared by conventional casting technique. The size, volume fraction and stability of the i-phase were found to be dependent on the Mn content. The addition of 2 at.% Cu did not affect the formation and stability of the i-phase but contributed significantly to the enhancement of the mechanical properties.