Settling the matter of the role of vibrations in the stability of high-entropy carbides.

High-entropy ceramics are attracting significant interest due to their exceptional chemical stability and physical properties. While configurational entropy descriptors have been successfully implemented to predict their formation and even to discover new materials, the contribution of vibrations to their stability has been contentious. This work unravels the issue by computationally integrating disorder parameterization, phonon modeling, and thermodynamic characterization.

Ordered structures in rhenium binary alloys from first-principles calculations.

Rhenium is an important alloying agent in catalytic materials and superalloys, but the experimental and computational data on its binary alloys are sparse. Only 6 out of 28 Re transition-metal systems are reported as compound-forming. Fifteen are reported as phase-separating, and seven have high-temperature disordered σ or χ phases.

Interatomic bonding and mechanical properties of trialuminides: an ab initio study for Al(3)(Sc,Ti,V) (abstract only).

On the basis of ab initio density-functional calculations we have analyzed the character of the interatomic bonding in the intermetallic compounds Al(3)(Sc,Ti,V) with the D0(22) and L1(2) structures. In all structures we found an enhanced charge density along the Al-transition-metal (TM) bonds, a characteristic feature of covalent bonding. The series Al3Sc-Al3V corresponds to gradual d-band filling which leads to a gradual increase of bond strength and covalent bond formation.