Elastic constants of B2-MgRE (RE = Sc, Y, La–Lu) calculated with first-principles

The elastic properties of B2-MgRE (RE=Sc, Y, La–Lu) intermetallic compounds have been calculated at T=0K by using first principles within the generalized gradient approximation (GGA). The calculated equilibrium lattice constants and bulk modulus are in agreement with the available experimental values. And the polycrystalline shear moduli, Young’s moduli, the ratio of bulk to shear modulus B/G are also estimated to insight the brittle/ductile behaviors of the B2-MgRE. The calculated results indicated that MgEu is the most brittle, and MgEr is the most ductile among the B2-MgRE alloys. The calculated polycrystalline shear modulus and Young’s modulus shown that the RE additions can improve the elastic properties of B2-MgRE compounds. The density of states and charge densities distribution of the B2-MgRE under deformation are calculated. The characteristic of elastic constants of B2-MgRE are explained by the insight of electronic structures under deformation.