Kinetic effect on the interaction between edge dislocations and stacking fault tetrahedra in FCC crystals

* Corresponding (email: mshuang@hust.edu.cn) This study investigates the interaction between an edge dislocation and an array of irradiated stacking fault tetrahedra (SFT) in face -centered cubic (FCC) Cu and Ag crystals using molecular dynamics/statics simulations and theoretical analysis. This study primarily aims to understand the kinetic inertia effect on the mechanisms of dislocation-SFT interaction and the critical resolved shear stress (CRSS) for the dislocation bypassing the SFT (i.e., the SFT strength). The results reveal at least five distinct dislocation-SFT interaction mechanisms (M1-M5). When the dislocation slip plane is located at a far enough distance away from the SFT base, the dislocation tends to directly cut through the SFT via the M1/M2 mechanisms. Conversely, if the dislocation slip plane is close enough to the SFT base plane, the dislocation opts to climb over the SFTs via the M3-M5 mechanisms. The change in CRSS for dislocations bypassing the SFTs relative to the size of the slip plane-SFT intersection displays a two -stage response when the dislocation-SFT interaction mechanisms transition. Although the kinetic effect of dislocation motion has a minimal impact on the dislocation-SFT interaction mechanism, it considerably decreases the CRSS for dislocations bypassing the SFTs. Therefore, a two -stage theoretical model of SFT-hardening behavior was developed, taking into account both the kinetic inertia effect and the transition of dislocation-SFT interaction mechanisms.