Abnormal Strain Rate Sensitivity Driven by a Unit Dislocation-Obstacle Interaction in bcc Fe

Abstract

The interaction between an edge dislocation and a sessile vacancy cluster in bcc Fe is investigated over a wide range of strain rates from 10^{8} down to 10^{3} s^{-1}, which is enabled by employing an energy landscape-based atomistic modeling algorithm. It is observed that, at low strain rates regime less than 10^{5} s^{-1}, such interaction leads to a surprising negative strain rate sensitivity behavior because of the different intermediate microstructures emerged under the complex interplays between thermal activation and applied strain rate. Implications of our findings regarding the previously established global diffusion model are also discussed.

Application of a FL Time Series Building Model in Mobile Network Interaction Anomaly Detection in the Internet of Things Environment

“…In addition to the attacks on the network, there are also attacks on the devices of the Internet of ings [7]. As IoT devices can generate high-dimensional data with obvious characteristics, such as temperature measurement, video monitoring, and water level telemetry, IoT devices have been deeply applied in many aspects [8,9]. e interaction of mobile network is mainly aimed at interaction behavior, because the interactive network is easy to accept, simple to operate, and so on and has been applied in many computer networks, bringing a lot of mobile network interaction behavior [10,11].…”

Effects of Re on Vacancy Mobility in a Ni-Re System: An Atomistic Study

“…A few examples showing the success of the activation/relaxation techniques include the modeling of long-timescale dynamics in the unfaulting mechanism of trapped atom clusters in bcc Fe [22], void nucleation and growth in bcc Fe [20,23], dislocation-defect interactions and their influence on the strain rate [24], anisotropic diffusion of point defects in hcp Zr [25], and thermally activated deformation in metallic glass [26]. Similar studies have been carried out in other material systems and proved to give new insights into the material kinetics [27][28][29][30][31][32][33].…”

Twinning-Induced Abnormal Strain Rate Sensitivity and Indentation Creep Behavior in Nanocrystalline Mg Alloy

“…With increasing strain rate, the amount of solute atoms that can follow mobile dislocations decreases, reducing motion resistance and leading to NSRS. Thus, at a fixed temperature, DSA can only work below a critical strain rate, beyond which solute atoms can no longer follow dislocations and dislocation-accumulation-induced PSRS takes over [54,55]. It is therefore appropriate to claim that the NSRS of the NC Mg alloy in the present work is not caused by the DSA effect for the following reasons.…”

“…However, under some specific circumstances, materials can soften at higher strain rates, showing a phenomenon of negative SRS (NSRS). By far, there are four mechanisms that can explain the NSRS phenomenon: dynamic strain ageing (DSA) [52][53][54][55], stress-induced phase transformation (SIPT) [56,57], formation of microcracks [54,58], and enhanced twinning activities at higher strain rates [59][60][61].…”