First Principle Study of MgSnLa Compounds in Mg-3Sn-1Mn-1La Alloy Processed by Rheo-Rolling.

In order to obtain a high-performance heat-resistant Mg alloy during the rheo-rolling process, the electronic structure, elastic constants, binding energy and thermodynamic properties of the MgSnLa compounds were conducted by first-principle calculations. The results show that the MgSnLa compounds (LaSn, MgLa and MgSn) all show certain metallicity, and LaSn has better mechanical properties (higher bulk modulus (46.47091 GPa) and shear modulus (26.40561 GPa)) than the other two phases. The binding energy reveals that LaSn is the most stable phase in these composite phases (5.33 eV/atom); additionally, thermodynamic studies show that the structural stability of the MgSnLa compounds increases with the increase in temperature, and the temperature has the greatest effect on the stability of MgLa. These all provide an efficient guide for the widespread engineering applications of high-performance heat-resistant Mg alloy.