Diffusion mechanism in cutting Ni-based alloy containing γ′ phase (Ni3Al) with CBN tool based on MD simulation

Ni-based alloys are widely used in aerospace because of their high strength and high temperature oxidation resistance. CBN tool is suitable for precision machining of Ni-based alloy. Diffusion wear is an important wear form of CBN tool in the process of cutting Ni-based alloy. Therefore, it is of great significance to study the diffusion phenomenon in the process of cutting Ni-based alloy with CBN tool. In this paper, the cutting model of Ni-based alloy containing γ′ phase (Ni3Al) with CBN tool is established based on the molecular dynamics (MD) simulation method. The self diffusion activation energy of all kinds of atoms in the workpiece and the formation energy of several point defects in the tool are calculated, so as to study in depth the atom diffusion mechanism according to the simulation results. The results show that the atoms in the crystal boundary of the workpiece are the most easily diffused, followed by the atoms in the phase boundary, and the atoms in the lattice are the most difficult to diffuse. When the workpiece atoms diffuse into the tool, it is easier to diffuse into the tool grain boundary than to form interstitial impurity atoms or displacement impurity atoms. It is more difficult to form the substitutional impurity atom than to form the interstitial impurity atom.

Green’s functions theory for an interstitial magnetic impurity in a transverse Ising ferromagnet

A Green’s function formalism is used to calculate the spectrum of localized states associated with an interstitial magnetic impurity in a semi-infinite ferromagnet described by the transverse Ising model. The nonresonant and resonant excitations of the system due to the impurity (i.e. the defect modes outside and inside, respectively, the region of the bulk and surface spin waves (SW)) are calculated numerically for the high-temperature phase. Two situations are analyzed, depending on the position of the interstitial impurity: the impurity is in the surface ([Formula: see text]) and the impurity is in the bulk region ([Formula: see text]).

Ab initio solute–interstitial impurity interactions in vanadium alloys: the roles of vacancy

This study aims to characterize the interactions between substitutional solutes (3d, 4d and 5d transition metals) and interstitial impurities (C and O) in vanadium alloys, with or without the presence of an adjacent vacancy.