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• The size- and stress-dependent dislocation-DLs interactions are investigated by MS and MD, with the emphasis focused on its kinetic effect. • The dislocation tends to fully absorb/transform small DLs but only to partially absorb/transform large ones. • When the dislocation is accelerated to subsonic speed, abnormal "pull-forward" configurations can be formed after it bypasses the small DLs. • The kinetic effect decreases the CRSS of dislocation bypassing DLs evidently. • Both amended DBH and BKS hardening models are proposed to consider the above kinetic effect. In this paper, the interaction between an edge dislocation and irradiation <100> sessile self-interstitial atom (SIA) type dislocation loops (DLs) is studied by atomistic simulations in BCC Ta at 0 and 300 K. Both molecular dynamics (MD) and statics (MS) simulations are performed to highlight the dislocation kinetic effect (or dynamic effect) on the critical resolved shear stress (CRSS) for dislocation bypassing the DLs and on the dislocation-SIA DLs interaction mechanisms. The simulation results show that the dislocation-DLs interaction mechanisms are two-fold. When the DL size is lower than a critical value, the moving edge dislocation tends to completely absorb the DLs or fully transform the original DLs into other-type ones. However, when the DL size is higher than the critical value, the moving dislocation tends to absorb or transform the DLs partially or even marginally. Moreover, with increasing applied shear stress, the high-speed dislocation has no sufficient time to absorb SIAs from DLs, which also changes the dislocation-DLs interaction process remarkably. When the dislocation is accelerated to subsonic, an abnormal "pull forward" dislocation configuration may present upon the dislocation bypasses a small DL. More importantly, with the kinetic effect considered, the CRSS for dislocation overcoming the barriers of DLs decreases significantly for the dislocation-DLs interaction mechanisms. In order to appropriately describe the kinetic effect on the CRSS, amended dispersed barrier hardening (DBH) and Bacon-Kocks-Scattergood (BKS) hardening models for the latter dislocation-DLs interaction mechanism are proposed. [Display omitted] [ABSTRACT FROM AUTHOR]

• With dynamic inertia effect considered, four dislocation-microvoid interaction mechanisms have been captured. • When the dislocation is accelerated to subsonic speed, the abnormal "pull-forward" dislocation configuration has been first captured. • With dynamic effect considered, the high-speed oscillation, "straight" and "pull-backforward" mechanisms can also be found. • The abnormal "supersonic wave cone" configuration is associated with the relative mobility between the original (110)[111] dislocation and the (112)[111] jog segment. • The abnormal configurations have been found for all considered BCC crystals Ta, Fe, V and W. The interaction between a high speed edge dislocation and a microvoid has been investigated by molecular dynamics (MD) simulations in BCC crystals of Ta, Fe, V and W in the present work. The focus is placed on the dynamic effect on the dislocation-microvoid interaction. Three interaction scenarios different from static cases, i.e., repeated dislocation oscillations around microvoids, dislocation depinning from microvoid like releasing an elastic slingshot, and formation of abnormal "pull forward" dislocation configuration, have been found for the first time. The "repeated oscillations" can be attributed to the dislocation line tension and dynamic effect, which is analogous to under-damped mechanical oscillator system. For the "releasing slingshot" case, the dislocation first bows out after breaking away from the microvoid, and then a stable "drag backward" dislocation configuration is formed. When further increasing the applied shear stress, the dislocation can accelerate to subsonic speed of roughly 0.7 C T , with C T being the transverse sound speed, leading to a stable "pull forward" configuration. These different dislocation configurations are closely related to the formation of superjog driven by the dislocation-microvoid interaction. By careful analysis, it is found that the variation of relative mobility between the original edge dislocation on the (110) plane and the superjog segments on the (112) plane with shear stresses perfectly coincides with the above three dislocation configurations. In fact, when the applied shear stress is high enough and the dislocation speed is subsonic, the friction stress on the superjog segments turns to be smaller than that of the original edge dislocation, resulting in the formation of abnormal "pull forward" configuration. [Display omitted] [ABSTRACT FROM AUTHOR]