Size-Tuned Plastic Flow Localization in Irradiated Materials at the Submicron Scale

Abstract

Three-dimensional discrete dislocation dynamics (3D-DDD) simulations reveal that, with reduction of sample size in the submicron regime, the mechanism of plastic flow localization in irradiated materials transitions from irradiation-controlled to an intrinsic dislocation source controlled. Furthermore, the spatial correlation of plastic deformation decreases due to weaker dislocation interactions and less frequent cross slip as the system size decreases, thus manifesting itself in thinner dislocation channels. A simple model of discrete dislocation source activation coupled with cross slip channel widening is developed to reproduce and physically explain this transition. In order to quantify the phenomenon of plastic flow localization, we introduce a "deformation localization index," with implications to the design of radiation-resistant materials.

Modeling the mechanical properties of nanoparticles: a review

“…In contrast with the superposition method, long-range dislocation interactions are computed by the FE code in the DCM. From our knowledge, while both methods were used to model nanoindentation tests [69,75], composite materials and alloys [76,77], crack initiation and propagation [78,79] as well as deformation of pillars, wires and thin films, at the micro-and nanoscales (see e.g., [80][81][82][83]), they have not been applied yet to investigate the mechanics of NPs. Obviously, mesoscale hybrid simulations such as the superposition method or the DCM would be of great help to better assess the mechanical properties and elementary deformation processes of NPs.…”

Influence of Size on the Fractal Dimension of Dislocation Microstructure

“…Irradiation defects themselves are not considered when discussing the fractal behavior of dislocation structures. More details on the simulation set-up and descriptions are given in [33,[38][39][40].…”

“…However, the obtained 3D dislocation structure information is still limited and not used to check their fractal behavior yet. On the other hand, discrete dislocation dynamics (DDD) simulations represent a powerful tool to investigate the formation of dislocation structure by considering the short-range and long-range dislocation interactions and external load conditions [32][33][34]. 2D-DDD reproduces the fractal dislocation structures in multiple slip [15].…”

Probing the Damage Recovery Mechanism in Irradiated Stainless Steels Using In-Situ Microcantilever Bending Test

“…Specifically, microcantilever bending has been used to determine hydrogen embrittlement with respect to hydrogen-induced cracking (Deng et al, 2017;Deng and Barnoush, 2018); quantify the fracture toughness and dislocation structures of brittle materials through site-specific investigation in thin films, single crystals, and grain boundaries (Iqbal et al, 2012;Zou et al, 2017;Alfreider et al, 2018;Ast et al, 2018;Ast et al, 2019); and probe the mechanical impact on ion-irradiated damage layers (Armstrong et al, 2015;Leide et al, 2020;Yano et al, 2020). HeIC initiation and propagation can also be investigated using site-specific micromechanical tests, where small-scale heterogeneity of structures and properties are prevalent, analogous to the irradiated materials (Diaz De La Rubla et al, 2000;Byun et al, 2006;Cui et al, 2018a), representing a manifestation of the localized mechanical degradation with an underlying irradiation-induced microstructure that is present at even finer scale such as clusters and channels (Patra and McDowell, 2013;Cui et al, 2018b;Cui et al, 2018c;Wharry et al, 2019).…”