Effect of doping IVB, VB and VIB elements on structure, stability, elastic and electronic properties of the O and B2 of Ti2AlNb intermetallic: A first principles study

Abstract

Abstract The intermetallic stability, structural, and elastic properties of the B2 and the O intermetallic of Ti2AlNb intermetallic doped with IVB, VB, and VIB elements of the periodic table are studied using density functional theory. The energy of formation and calculated elastic constants reveal that all the doped intermetallics are thermodynamically and mechanically stable. The derived elastic moduli and Pugh's ratio confirm that doping with quaternary elements can enhance the mechanical properties and ductility of the Ti2AlNb intermetallic in both the B2 and the O intermetallic. Further, elements that enhance the ductility and hardness in the O intermetallic, decrease the same in the B2 intermetallic. Among all the systems, Mo and W provide the most enhancement in B, G, and E values in both the B2 and O intermetallic. Ductility of the B2 intermetallic is most enhanced by Ti and Nb while of the O intermetallic by Cr and Mo. All the dopants increase the melting point where W provides the most enhancement. Poisson's ratio, hardness, and Cauchy pressures are further investigated. The electronic density of states indicates that dopants induce redistribution of charge due to new bond formations resulting to a significant change in intermetallic stability and mechanical properties.