Simulation of single slip in FCC metals

Abstract

The study of single slip was performed by imitation simulation and mathematical simulation methods. In a modified barrier model of constant linear tension, all stages of the process of nucleation and propagation of single crystallographic slip to the field of discrete dislocation obstacles have been simulated and investigated. The equation of dynamics of expansion of an isolated closed planar dislocation loop, which restricts slipping, was used to perform a comparative study of the effect of the mechanisms of resistance to dislocation motion on the characteristics of the resulting single slip. Micromechanical characteristics of each dislocation loop emitted by a dislocation source after loss of stability have been calculated. The time it takes for single slip to propagate up to the barrier configurations that restrict slipping and the total formative time of the crystallographic shear zone have been estimated.

Mathematical Modeling of Plastic Deformation in FCC Metals

“…The investigations were carried out on the basis of a mathematical model of crystallographic slip dynamics (1). The values of the basic parameters of the model used according to independent experimental and theoretical studies of various authors.…”

“…At a minimum length d of a dislocation source, at which emission of dislocation loops is possible, defined as [1]: d = ( √ 0, 14ξρ) −1 , the number of dislocations in the shear zone in copper, aluminum and lead varies insignificantly and is equal to ≈ 30.…”

“…k is the kinetic energy per unit length of the moving i th dislocation emitted by the dislocation source, r is the radius of the dislocation loop, ξ is the Smallman multiplier, p j is the fraction of threshold-forming dislocations of noncoplanar slip systems, p s is the fraction of threshold-forming dislocations on the outline segments of the dislocation loop, c is the sound velocity in the crystal, B is the coefficient of viscous inhibition, G is the shear modulus, b is the modulus of the Burgers vector, ν is the Poisson's ratio, ρ is the dislocation density, D is the shear zone diameter, µ 0 is the linear tension of the dislocation, τ R = τ f + τ d , where τ f is the stress of the lattice and impurity friction, τ d = αGρ 1/2 is the dislocation resistance to the propagation of crystallographic slip, α is the parameter characterizing the intensity of interdislocation interactions. The terms on the right-hand side of the first equation of system (1) represent, respectively, the Pich-Kohler force and the resistance forces due to: the action of inverse stress fields from the side of the dislocation cluster, the linear tension of the moving dislocation, the overcoming of lattice, impurity and dislocation friction, viscous inhibition and point defects generation.…”

“…Such a set of emerging dislocations forms a zone of crystallographic shear [1]. Crystallographic shear zone is decisive structural element of crystallographic slip.…”

Governance of the Russian Higher Education System in the Light of an Innovative Development Path Selected

“…External factors are defined by the modern conditions of the subjective nature (Popov et al, 2015), such as global and civilizational crisis, biosphere-ecological crisis, and the ideological (i.e. world outlook) crisis.…”