First Principles Calculations of Solute Sweeping and Stacking Faults in Mg-Zn-Y Alloy

Abstract

The formation mechanism of the long-period stacking-ordered (LPSO) structure of a Mg-Zn-Y alloy was investigated through energy assessments using first-principles calculations. The solute atoms are swept out from stacking fault regions because of their repulsive interaction with precipitated L1 2 clusters. The swept-out solute atoms are condensed a few layers away from the stacking-fault regions and accelerate the introduction of other stacking faults. A new scenario in the formation of the LPSO structure is proposed.

Study on the planar segregation of solute atoms in Mg-Al-Gd alloy

“…Only layers 1~6 in Figure 4(a) are considered due to the mirror symmetry of this structure. It is noted that there are different inequivalent sites on each layer [31]. In our model, the inequivalent sites in layer A and C are shown in Figure 4(b) and (c), respectively.…”

“…Since the G.P. zone appears together with SU, 6 the interaction between solute atoms and the SU is considered similar to the study in Mg-Zn-Y system [31]. The atomic model is shown in Figure 4(a), where twenty layers containing two ordered SUs are modeled.…”