Phase stability, electronic structure and mechanical properties of Cr and Ti doped Pt₃Al: first-principles calculations

The effects of doping Cr and Ti alloying atoms on the electronic structure and elastic properties of Pt3Al are investigated using a first-principles calculations based on density functional theory. The negative values of formation enthalpy and cohesive energy show that these alloys are thermodynamically stable. Meanwhile, the site of the Al atom in Pt3Al is the most favorable doping site for Cr and Ti atoms. It is found that Cr and Ti can stabilize the L12-Pt3Al phase when occupy the Al sites. The calculated results of electronic structure show that a common hybridization formed near Fermi level, which revealed that the Pt-Pt, Pt-Al, and Pt-Cr or-Ti bonds were formed. The elastic properties, including bulk modulus, shear modulus, Young' s modulus and Poisson' s ratio, are calculated by Viogt-Reuss-Hill approximation. The calculated results reveal that all alloys in our work are ductile, and Ti-Al(3) alloy posses the highest hardness.