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

Abstract

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 (La₅Sn₃, Mg₁₇La₂ and Mg₂Sn) all show certain metallicity, and La₅Sn₃ 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 La₅Sn₃ 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 Mg₁₇La₂. These all provide an efficient guide for the widespread engineering applications of high-performance heat-resistant Mg alloy.

Keywords: MgSnLa compounds; first principle; heat-resistant Mg alloy; rheo-rolling; thermodynamic properties.