First-Principles Study on Thermodynamic, Structural, Mechanical, Electronic, and Phonon Properties of tP16 Ru-Based Alloys

Transition metal-ruthenium alloys are promising candidates for ultra-high-temperature structural applications. However, the mechanical and electronic characteristics of these alloys are not well understood in the literature. This study uses first-principles density functional theory calculations to explore the structural, electronic, mechanical, and phonon properties of X3Ru (X = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) binary alloys in the tP16 crystallographic phase. We find that Mn3Ru, Sc3Ru, Ti3Ru, V3Ru, and Zn3Ru have negative heats of formation and hence are thermodynamically stable. Mechanical analysis (Cij) indicates that all tP16-X3Ru alloys are mechanically stable except, Fe3Ru and Cr3Ru. Moreover, these compounds exhibit ductility and possess high melting temperatures. Furthermore, phonon dispersion curves indicate that Cr3Ru, Co3Ru, Ni3Ru, and Cu3Ru are dynamically stable, while the electronic density of states reveals all the X3Ru alloys are metallic, with a significant overlap between the valence and conduction bands at the Fermi energy. These findings offer insights into the novel properties of the tP16 X3Ru intermetallic alloys for the exploration of high-temperature structural applications.