Dislocation nucleation and interface sliding are two dominant plasticity events governing the mechanical behavior of metallic nanocomposites. Recent works have shown that both events can be closely related to atomistic interface geometries, however, how compositional factors, e.g., segregated hydrogen clusters, contribute both events are nearly unk...
Misfit dislocations at bimetal interfaces play a key role in interface-induced deformation mechanism, which in turn determines the strengthening and softening at different length scales. Although a variety of interfaces have been explored to reveal distinct misfit dislocations and resultant deformation mechanisms, an ideal clean bimetal interface m...
Interface-facilitated dislocation nucleation dominates deformation behaviors of metallic nanolaminates under shock loadings. Recent works demonstrated a strong size effect of dislocation nucleation for bimetal nanolaminates. Herein, we demonstrate that such effect is attributed to stress effect of misfit dislocations originating from neighboring in...
Published in Royal Society open science
The effects of Re, W and Co on dislocation nucleation at the crack tip in Ni have been studied by the molecular dynamics method. The results show that the activation energy of dislocation nucleation is lowered by the addition of Re, W and Co; moreover, the activation energy decreases when the alloying element increases from 1 at.% to 2 at.%. The en...
Incipient plasticity in multi-principal element alloys, CoCrNi, CoCrFeMnNi, and Al0.1CoCrFeNi was evaluated by nano-indentation and compared with pure Ni. The tests were performed at a loading rate of 70 &mu / N/s in the temperature range of 298 K to 473 K. The activation energy and activation volume were determined using a statistical approach of ...
The homogenization of dislocation dynamics including the mechanisms of dislocation nucleation is a great challenge in dislocation based continuum formulations. Due to the loss of the local and temporal resolution in a continuum model, physical nucleation mechanisms have to be incorporated in an average sense. Consequences can be the over- or undere...
Low-energy structures of bimetal interfaces commonly occur in nature, yet higher energy forms, made by deviations in the interface plane, are also likely. While these variants may occur less frequently, they can still play an important role in the response of the material under deformation, by acting as preferential sites for defect formation and b...
Misfit dislocations at bimetal interfaces play a decisive role in determining various deformation behaviors by carrying the shear sliding, serving as a barrier for dislocation transmission and a source of dislocation nucleation. However, when the interface does not possess the distinct feature of misfit dislocations, the nucleation mechanism of lat...
Misfit dislocation pattern is generally accepted to play a critical role on the interface mediated deformation mechanism such as dislocation nucleation and shear sliding in various flat interfaces, however, a specific mechanical loading may dynamically modify its distribution and character before the appearance of distinct plastic flow out of inter...
We propose a framework to study thermally-activated processes in dislocation glide. This approach is based on an implementation of the nudged elastic band method in a nodal mesoscale dislocation dynamics formalism. Special care is paid to develop a variational formulation to ensure convergence to well-defined minimum energy paths. We also propose a...
