Thick interface size effect on dislocation transmission in nanolaminates

Abstract

Recent experimental studies have reported that thick interfaces in nanolaminates can lead to greater strengths than conventionally sharp interfaces without sacrificing deformability. Using a multi-phase phase-field dislocation dynamics model, dislocation transmission across a compositionally graded, nanoscale thick interface is investigated. Thicker interfaces over a finite range are found to lead to greater resistance to transmission. The limit interface thickness at which the peak resistance is reached, and the strengthening capacity of the interface are greater when the dislocation is dissociated, as in a face-centered cubic lattice, than when it is compact, as in a body-centered cubic lattice. The composition transitions within the interface are treated with multiple sublayers, and it is found that the interface transmission barrier is as strong as its most resistance composition.