Investigation on the icosahedral quasicrystal phase in Mg 70.8Zn 28Nd 1.2 alloy

Abstract

Mg 70.8Zn 28Nd 1.2 (mole fraction) alloy containing icosahedral quasicrystal phase (I-phase) was prepared under conventional metal casting conditions. The microstructure, phase constitution and phase structure of the alloy were investigated by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and transmission electron microscopy (TEM). The results showed that the spherical phase in Mg 70.8Zn 28Nd 1.2 alloy was a simple icosahedral quasicrystal with stoichiometric composition of Mg 40Zn 55Nd 5 and quasi-lattice of 0.525 nm. In this research, the as-cast microstructure of Mg 70.8Zn 28Nd 1.2 alloy mainly consisted of Mg 40Zn 55Nd 5 icosahedral quasicrystal phase and Mg 7Zn 3 columnar crystal matrix. In the growing process of Mg 40Zn 55Nd 5 icosahedral quasicrystal phase, the growth morphology mainly depended on interface energy, adsorption effect of Nd and cooling rate.