Investigation on Thermodynamic Stability of 10H and 14H Long Period Stacking Ordered Phase in Mg-Zn-Y Alloy

Abstract

In this paper, enthalpies of formation and electronic structures of long period stacking ordered phases in ternary Mg-Zn-Y alloys are calculated by first-principles. Through calculations of the enthalpies of formation, it was found that enthalpies of formation of 10H phase and 14H phase are negative, and the enthalpy of formation of 10H phase less than that of 14H phase. It shows that both phases can form stable structure. The energy of transformation calculations show that 14H phase is more stable than 10H phase. The analysis of electronic structure shows that the difference between the structural stability of 10H phase and 14H phase is due to the different number of bonding electrons at the lower energy level of Fermi level. More bonding electrons determine that 14H phase has better stability than 10H phase.