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It has been shown in experiments that self-climb of prismatic dislocation loops by pipe diffusion plays important roles in their dynamical behaviors, e.g., coarsening of prismatic loops upon annealing, as well as the physical and mechanical…

Materials Science · Physics 2019-05-21 Xiaohua Niu , Yejun Gu , Yang Xiang

We develop a mesoscopic dislocation dynamics model for vacancy-assisted dislocation climb by upscalings from a stochastic model on the atomistic scale. Our models incorporate microscopic mechanisms of (i) bulk diffusion of vacancies, (ii)…

Materials Science · Physics 2016-12-21 Xiaohua Niu , Tao Luo , Jianfeng Lu , Yang Xiang

The effects of dislocation climb on plastic deformation during loading and unloading are studied using a two-dimensional discrete dislocation dynamics model. Simulations are performed for polycrystalline thin films passivated on both…

Materials Science · Physics 2014-01-03 Kamyar M. Davoudi , Lucia Nicola , Joost J. Vlassak

Plastic deformation In crystalline materials is controlled by the motion and interactions of dislocations [AND 17]. Discrete Dislocation Dynamics (DDD) simulations have now existed for about 25 years to investigate plastic flow at the…

Materials Science · Physics 2020-01-07 Sylvain Queyreau

We report two-dimensional discrete dislocation dynamics simulations of combined dislocation glide and climb leading to `power-law' creep in a model aluminum crystal. The approach fully accounts for matter transport due to vacancy diffusion…

Mesoscale and Nanoscale Physics · Physics 2017-12-27 Shyam M. Keralavarma , Tahir Cagin , Tom Arsenlis , A. Amine Benzerga

Pinning interaction between a screw dislocation and a void in fcc copper is investigated by means of molecular dynamics simulation. A screw dislocation bows out to undergo depinning on the original glide plane at low temperatures, where the…

Materials Science · Physics 2008-02-16 Takahiro Hatano , Tetsuya Kaneko , Yousuke Abe , Hideki Matsui

Over the past decades, discrete dislocation dynamics simulations have been shown to reliably predict the evolution of dislocation microstructures for micrometer-sized metallic samples. Such simulations provide insight into the governing…

Dislocation climb plays an important role in understanding plastic deformation of metallic materials at high temperature. In this paper, we present a continuum formulation for dislocation climb velocity based on densities of dislocations.…

Materials Science · Physics 2023-08-15 Chutian Huang , Shuyang Dai , Xiaohua Niu , Tianpeng Jiang , Zhijian Yang , Yejun Gu , Yang Xiang

Recently, a dislocation free deformation mechanism was proposed by Kiritani et al., based on a series of experiments where thin foils of fcc metals were deformed at very high strain rates. In the experimental study, they observed a large…

Materials Science · Physics 2015-06-24 J. Schiøtz , T. Leffers , B. N. Singh

Topological defects play an important role in physics of elastic media and liquid crystals. Their kinematics is determined by constraints of topological origin. An example is the glide motion of dislocations which has been extensively…

Strongly Correlated Electrons · Physics 2008-02-11 V. Cvetkovic , Z. Nussinov , J. Zaanen

We employ the methods of atomistic simulation to investigate the climb of edge dislocation at nanovoids by analyzing the energetics of the underlying mechanism. A novel simulation strategy has been demonstrated to estimate the release of…

Materials Science · Physics 2013-04-22 A. Dutta , M. Bhattacharya , N. Gayathri , G. C. Das , P. Barat

Dipolar dislocation loops, prevalent in fcc metals, are widely recognized as controlling many physical aspects of plastic deformation. We present results of 3D dislocation dynamics simulations that shed light on the mechanisms of their…

Materials Science · Physics 2017-01-02 Can Erel , Giacomo Po , Tamer Crosby , Nasr Ghoniem

In this paper, we present a phase field model for the self-climb motion of prismatic dislocation loops via vacancy pipe diffusion driven by elastic interactions. This conserved dynamics model is developed under the framework of the…

Materials Science · Physics 2020-12-04 Xiaohua Niu , Yang Xiang , Xiaodong Yan

Dislocation motion in body centered cubic (bcc) metals displays a number of specific features that result in a strong temperature dependence of the flow stress, and in shear deformation asymmetries relative to the loading direction as well…

Materials Science · Physics 2016-08-05 Giacomo Po , Yinan Cui , David Rivera , David Cereceda , Tom D. Swinburne , Jaime Marian , Nasr Ghoniem

A continuum theory based on thermodynamics has been developed for modeling diffusional creep of polycrystalline solids. It consists of a coupled problem of vacancy diffusion and mechanics where the vacancy generation/absorption at grain…

Materials Science · Physics 2019-11-18 M. Magri , G. Lemoine , L. Adam , J. Segurado

The continuum dislocation dynamics framework for mesoscale plasticity is intended to capture the dislocation density evolution and the deformation of crystals when subjected to mechanical loading. It does so by solving a set of transport…

Materials Science · Physics 2021-02-24 Vignesh Vivekanandan , Peng Lin , Grethe Winther , Anter El-Azab

Recent experiments by Kiritani et al. have revealed a surprisingly high rate of vacancy production during high-speed deformation of thin foils of fcc metals. Virtually no dislocations are seen after the deformation. This is interpreted as…

Materials Science · Physics 2022-11-09 J. Schiøtz , T. Leffers , B. N. Singh

Understanding plastic deformation of crystals in terms of the fundamental physics of dislocations has remained a grand challenge in materials science for decades. To overcome this, the Discrete Dislocation Dynamics (DDD) method has been…

Materials Science · Physics 2024-04-03 Nicolas Bertin , Wei Cai , Sylvie Aubry , Athanasios Arsenlis , Vasily V. Bulatov

Dislocations are the carriers of plasticity in crystalline materials. Their collective interaction behavior is dependent on the strain rate and sample size. In small specimens, details of the nucleation process are of particular importance.…

Materials Science · Physics 2020-11-05 Jianqiao Hu , Hengxu Song , Zhanli Liu , Zhuo Zhuang , Xiaoming Liu , Stefan Sandfeld

The two-dimensional dislocation dynamics approach has been recently used for analyzing plastic deformation in metals and alloys at elevated temperatures. The two-dimensional approach, however, only accounts for the dislocation climbing…

Materials Science · Physics 2018-01-29 Amirreza Keyhani
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