Effect of P impurity on NiAlΣ5 grain boundary from first-principles study

Abstract

First-principles calculations based on the density functional theory (DFT) and ultra-soft pseudopotential are employed to study the atomic configuration and charge density of impurity P in NiAl Σ5 grain boundary (GB). The negative segregation energy of a P atom proves that a P atom can easily segregate in the NiAl GB. The atomic configuration and formation energy of the P atom in the NiAl GB demonstrate that the P atom tends to occupy an interstitial site or substitute a Al atom depending on the Ni/Al atoms ratio. The P atom is preferable to staying in the Ni-rich environment in the NiAl GB forming P-Ni bonds. Both of the charge density and the deformation charge imply that a P atom is more likely to bond with Ni atoms rather than with Al atoms. The density of states further exhibits the interactions between P atom and Ni atom, and the orbital electrons of P, Ni and Al atoms all contribute to P-Ni bonds in the NiAl GB. It is worth noting that the P-Ni covalent bonds might embrittle the NiAl GB and weakens the plasticity of the NiAl intermetallics.

Structural, electronic, and mechanical properties of cubic TiO2: A first-principles study

“…[19] In the same way, Hu et al carried out a deep study on the electronic and other properties using density functional theory (DFT) and other ultra-soft pseudopotentials. [20] From the literature, it is clear that numerous investigations have been carried out for natural TiO 2 . Additionally, a few investigations on the structural, electronic, and elastic properties for a catalytic material are also available.…”

Effect of P impurity on mechanical properties of NiAl Σ5 grain boundary: From perspectives of stress and energy

“…In our previous study, [14] we demonstrated that impurity P prefers to segregate in NiAl GB rather than in NiAl bulk. In most part of the range of the permissible chemical potential, P atom tends to occupy interstitial site that is in the Ni-rich environment in NiAl GB; in the extremely Ni-rich environment in NiAl GB, P atom prefers to substitute Al atom that is the first nearest to GBs.…”

“…According to the previous study, the solution energy E S GB of P in NiAl GB at the most stable site is −5.70 eV. [14] Hence, ∆E is calculated to be −0.65 eV, which indicates that P prefers to stay in NiAl Σ5 (310) free surface rather than in NiAl GB. That is, P impurity embrittles the NiAl Σ5 GB.…”

Effect of nickel segregation on CuΣ9 grain boundary undergone shear deformations

“…[14][15][16] Meanwhile, atomic scale simulation is also an essential approach to the exploration of the mechanism of how the GB segregation affects the mechanical properties of materials from energetic and electronic aspects. [17][18][19] According to the firstprinciples calculations, Lozovoi et al [20] have determined that the embrittlement of impurity segregation is attributed to either structure effect or electronic effect in a binary copper alloy. Zhang et al [21] further analyzed the effect of dense impurity segregation at GB on the plastic evolution of aluminum alloy.…”