High-Throughput Predictions of the Stabilities of Multi-Type Long-Period Stacking Ordered Structures in High-Performance Mg Alloys.

Abstract

The effects of 44 types of elements on the stabilities of I1-constitute multi-type long-period stacking-ordered (LPSO) structures in Mg alloys, such as 4H, 6H, 8H, 9R, 12H, 15R, and 16H phases, are systematically investigated by first-principle high-performance calculations. The intrinsic stacking-fault energies (ISFEs) and their increments are calculated along with the formation enthalpies of solute atoms, and interaction energies between solute atoms and LPSO structures. The results suggest that the 15R phase is the easiest to form and stabilize among these LPSO structures, and 44 types of solute atoms have different segregation characteristics in these LPSO structures. A high temperature inhibits structural stabilizations of the LPSO phases, and these alloying elements, such as elements (Sb, Te, and Cs) for 4H; elements (S, Fe, Sb, and Te) for 6H, 8H, 9R, 15R, and 16H; and elements (S, Sb, and Te) for 12H, can effectively promote the stability of LPSO structures at high temperatures. S and Fe atoms are the most likely to promote the stabilities of the 16H structure with regard to other LPSO phases, but the Fe atom tends to inhibit the stabilities of 4H and 12H structures. This work can offer valuable references to further study and develop high-performance Mg alloys with multi-type LPSO structures.