Elastic properties and electronic structures of Y atom solid solute supercell γ-Fe

摘要

Elastic properties and electronic structures of a Y atom solid solute supercell γ-Fe structure, which includes either a Y atom octahedral interstitial solid solute (Y-OISS), a Y atom tetrahedral interstitial solid solute (Y-TISS), a Y atom vertex substitutional solid solute (Y-VSSS) and a Y atom face-centered substitutional solid solute (Y-FSSS) have been calculated using a first-principles density functional theory plane-wave ultrasoft pseudopotential method, i.e. the Generalized Gradient Approximation (GGA) Perdew–Burke– Ernzerhof (PBE) exchange–correlation functional. The results indicate that, the Y-VSSS and Y-FSSS supercell γ-Fe are stable, while the Y-OISS and Y-TISS supercell γ-Fe are both unstable, especially Y-TISS. The bulk moduli of the Y-OISS, Y-TISS, Y-VSSS and Y-FSSS supercell γ-Fe are 234.72, 200.32, 262.45 and 262.56 GPa, and the shear moduli are 74.23, 52.02, 156.78 and 156.76 GPa, which shows that the directional bonding in Y-SSS supercell γ-Fe is stronger than that in Y-ISS and that the Y-ISS supercell γ-Fe is much stiff than the Y-SSS. The ratios between the shear modulus and bulk modulus of Y-OISS, Y-TISS, Y-VSSS and Y-FSSS supercell γ-Fe are 0.32, 0.26, 0.60 and 0.60, respectively, which implies that the Y-SSS supercell γ-Fe is essentially brittle and that the Y-ISS is slightly ductile. Poisson’s ratio of them are 0.47, 0.38, 0.25 and 0.35, which shows that compared with Y-ISS supercell c-Fe, the Y-SSS supercell c-Fe has good plasticity in the investigated binary alloys. The universal elastic anisotropy indexes of the Y-OISS, Y-TISS, Y-VSSS and Y-FSSS supercell γ-Fe are 1.765, 1.205, 0.965 and 0.95, the result indicates that the anisotropy decreases in the following sequence: Y-OISS supercell γ-Fe > Y-TISS > Y-FSSS > Y-VSSS. The amounts of transferred charges (per supercell) from Fe atom to Y atom is in the order of Y-VSSS supercell γ-Fe = Y-FSSS > Y-TISS > Y-OISS, respectively, which indicates that their ionicity is Y-VSSS supercell γ-Fe = Y-FSSS > Y-TISS > Y-OISS. By analyze the calculated results, the properties of the different Y atom solid solute supercell γ-Fe can be obtained, so as to provide theoretical support for the actual production.