Effect of transition metal doping on Cr–Ru alloys using first principles approach

Ab-initio density functional theory calculations have been used to explore the effect of transition metal alloying on A15 Cr–Ru intermetallic alloys. We study the structural, electronic and mechanical properties of ${\text{Ru}}_3\text{Cr}$ and ${\text{Cr}}_3\text{Ru}$ alloys doped with transition metals ($\text{M}=\text{Mn},\text{Mo},\text{Pt},\text{Pd},\text{Fe},\text{Co},\text{Re and Zr}$). Their thermodynamic and mechanical behaviours were deduced from the heat of formation, ratio of bulk to shear modulus, density of states (DOS) as well as elastic constants predictions. We find that Mn doping in these alloys leads to thermodynamic stability. These compounds also show a valence–conduction band overlap around the Fermi energy as depicted by the DOS. Furthermore, the Pugh ratio (the ratio of bulk to shear modulus) indicates the ductility character of these compounds. Their mechanical stability was illustrated by the Bohr mechanical stability criteria with all the elastic constants having a value >0. These results demonstrate that these systems can potentially be used as coating materials in high temperature structural applications.