The Portevin-Le Chatelier (PLC) effect is a phenomenon by which plastic slip in metallic materials becomes unstable, resulting in jerky flow and the onset of inhomogeneous deformation. The PLC effect is thought to be fundamentally caused by the dynamic interplay between dislocations and solute atoms. However, this interplay is almost always inaccessible experimentally due to the extremely fine length and time scales over which it occurs. In this paper, simulations of jerky flow in W-O interstitial solid solutions reveal three dynamic regimes emerging from the simulated strain rate-temperature space: one resembling standard solid solution strengthening, another one mimicking solute cloud formation, and a third one where dislocation/solute coevolution leads to jerky flow as a precursor of dynamic strain aging. The simulations are carried out in a stochastic framework that naturally captures rare events in a rigorous manner, providing atomistic resolution over diffusive time scales using no adjustable parameters.
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http://dx.doi.org/10.1038/s41467-020-15085-3 | DOI Listing |
Materials (Basel)
September 2024
School of Energy and Power Engineering, Dalian University of Technology, Dalian 116024, China.
An enhancement in fatigue life for ferrite-pearlite low-carbon steel (LCS) at high temperature (HT) has been discovered, where it increased from 190,873 cycles at room temperature (RT) to 10,000,000 cycles at 400 °C under the same stress conditions. To understand the mechanism behind this phenomenon, the evolution of microstructure and dislocation density during fatigue tests was comprehensively investigated. High-power X-ray diffraction (XRD) was employed to analyze the evolution of total dislocation density, while Electron Backscatter Diffraction (EBSD) and High-Resolution EBSD (HR-EBSD) were conducted to reveal the evolutions of kernel average misorientation (KAM), geometrically necessary dislocations (GND) and elastic strains.
View Article and Find Full Text PDFNeurologist
March 2024
Medicine Department, Federal University of Santa Maria, Santa Maria, Brazil.
Background: Limb-shaking is one of the transient ischemic attacks (TIA) 'chameleons.' This literature review aims to evaluate the clinical, epidemiological profile, pathologic mechanisms, and management of limb-shaking TIA.
Review Summary: Relevant reports in Medline's (PubMed) database were identified and assessed by 2 reviewers without language restriction from 1985 to 2022.
J Colloid Interface Sci
October 2022
Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S1 3JD, UK; School of Pharmacy, Changzhou University, Changzhou 213164, China. Electronic address:
Hypothesis: Microscopic self-propelled motors (SPMs) are an area of active research, but very little investigation has been conducted on millimetre-scale or macroscopic SPMs and exploring their potential in biomedical research. In this study, we tested if 3D reactive inkjet (RIJ) printing could be used for precise fabrication of millimetre-scale self-propelled motors (SPMs) with well-defined shapes from regenerated silk fibroin (RSF) by converting water soluble RSF (silk I) to insoluble silk fibroin (silk II). Secondly, we compared the different propulsion behaviour of the SPMs to put forward the best geometry and propulsion mechanism for potential applications in enhancing the sensitivity of diffusion-rate limited biomedical assays by inducing fluid flow.
View Article and Find Full Text PDFMaterials (Basel)
May 2020
Microstructure Physics and Alloy Design, Max-Planck-Institut für Eisenforschung,40237 Düsseldorf, Germany.
The interplay of interface and bulk dislocation nucleation and glide in determining the motion of twin boundaries, slip-twin interaction, and the mechanical (i.e., stress-strain) behavior of fcc metals is investigated in the current work with the help of molecular dynamics simulations.
View Article and Find Full Text PDFNat Commun
March 2020
Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, CA, 90095, USA.
The Portevin-Le Chatelier (PLC) effect is a phenomenon by which plastic slip in metallic materials becomes unstable, resulting in jerky flow and the onset of inhomogeneous deformation. The PLC effect is thought to be fundamentally caused by the dynamic interplay between dislocations and solute atoms. However, this interplay is almost always inaccessible experimentally due to the extremely fine length and time scales over which it occurs.
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