Effect of Alloying Elements on the Mechanical Properties of Mo3Si

Abstract

Molybdenum silicides are attractive high-temperature structural materials because of their excellent thermal stability and outstanding oxidation resistance at high temperatures. First-principles calculations were employed to investigate the effect of alloying elements (Cr, Nb, V, W, Al, Ga, and Ge) on the mechanical properties of Mo3Si. The structural stabilities of doped Mo3Si were calculated, showing that the Pm-3n structure was stable at the investigated low-doping concentration. The calculated elastic constants have also evaluated some essential mechanical properties of doped Mo3Si. Cr- and V-doping decreased the elastic modulus, while Al- and Nb-doping slightly increased the shear and Young’s modulus of Mo3Si. Furthermore, V-, Al- and Nb-doping decreased the B/G and Poisson ratio, suggesting that these elements could form strong covalent bonds, and decrease shear deformation and alloy ductility. Based on the three-dimensional contours and two-dimensional projection of the elastic modulus, Cr- and V-doping exhibited a significant influence on the anisotropy of the shear and Young’s modulus. According to charge density and density of states, the electronic structures of alloyed Mo3Si were further analyzed to reveal the doping effects.

Electronic and optical properties of nickel-doped ceria: A computational modelling study

“…To assess the stability of the chosen doped matrix along with the difficulty of Ni-doping such a system, the doping formation energy (E f ) has been computed for the systems via the following relationship [25]: The negative values of doping formation energy depicted in Table 1 indicate that the selected structures are stable and some amount of energy is released with the introduction of Ni atoms into the host system. Regarding the comparison between the current system and the system studied in Ref.…”