Contribution of interstitial migration to segregation in concentrated alloys

Radiation-Induced Segregation

“…From a microscopic description of the jump mechanism, one derives the kinetic equations associated with each dumbbell composition. [109][110][111][112] Unlike previous models, there is no local equilibrium assumption, but correlation effects are neglected (except in Bocquet 90 ). They could have used the interstitial diffusion model with the correlations of Bocquet.…”

“…40 Differences between the observed RIS are explained by a so-called grain boundary efficiency, introduced in a modified rate equation model. 40,109,114,124 Calculations of vacancy formation energies at different grain boundaries, for example, in nickel in which atomic interactions are described by an embedded atom method, have been used to model sink strength as a function of misorientation angle. The resulting RIS predictions around several tilt grain boundaries were found to be in good agreement with RIS data.…”

Diffusion and conversion of interstitial dumbbells in segregated ternary alloys under irradiation

“…The next terms describe all possible conversion of AA-dumbbell [6,7]. The term 1/2 is necessary because migration of interstitial dumbbell is realized by jump of the one atom of the dumbbell onto an adjacent lattice site.…”

“…The contribution of interstitial flux to radiation-induced segregation was considered as an interstitial migration. In the interstitial migration, one atom of the dumbbell jumps onto an adjacent lattice site forming a new dumbbell there, and the other atom left behind returns to the lattice site [6,7].…”

A defect-based model of radiation-induced segregation to free surfaces in binary alloys

“…On the contrary, the models in [2][3][4][5][6] predicted that nickel enrichment or chromium depletion at the grain boundaries should increase with nickel and chromium concentrations, respectively. This anomaly was later resolved by Murphy [8] when he proposed a model for multi-component systems under irradiation in which contribution of the interstitials to RIS was also considered. Interstitial contribution to RIS was explained by introducing a coupling between an interstitial and a lattice atom during the diffusion of dumbbell interstitials.…”