First principles studies on the structural, elastic, electronic properties and heats of formation of Mg–AE (AE = Ca, Sr, Ba) intermetallics

First principles calculations have been performed to study the structural, heats of formation, elastic properties, and densities of states of eight Mg–AE (AE = Ca, Sr, Ba) intermetallic compounds. The obtained results indicate that with increasing atom weight and concentration of AE, the bulk moduli decrease monotonously, and the larger the electronegativity difference is, the smaller the elastic modulus would be. Based on the ratios of shear moduli to bulk moduli, it has been found that Mg2Ca, Mg38Sr9, Mg2Sr, Mg17Ba2 and Mg23Ba6 behave in a brittle manner, and Mg17Sr2, Mg23Sr6 and Mg2Ba behave in a ductile manner. Our calculations of the densities of states, heats of formation, and elastic constants of all the eight Mg compounds indicate that they are all conductors, thermodynamically and mechanically stable.