A quasistatic implementation of the concurrent atomistic-continuum method for FCC crystals

Abstract

2016-11-02T18:49:00

Modeling Plastic Deformation of Nano/Submicron-Sized Tungsten Pillars Under Compression: A Coarse-Grained Atomistic Approach

“…However, MD simulations of submicro-/micropillars are exceedingly expensive-to the author's best knowledge, the largest atomistic pillar models to date contained about 45 million atoms (Gu et al, 2012;Xu et al, 2017a,b), with the maximum D = 70 nm (i.e., in the nanopillar regime). Therefore, in this paper, a coarse-grained atomistic approach named the concurrent atomistic-continuum (CAC) method (Chen, 2009;Xiong et al, 2011;Xu et al, 2015) is employed to explore the plastic deformation of nano-/submicron-sized metallic pillars. As a concurrent partitioned-domain multiscale modeling technique, the CAC simulation scheme usually partitions the whole problem into two domains: an atomistic domain and a coarse-grained domain (Xu and Chen, 2018).…”

Uniaxial stress-driven grain boundary migration in Hexagonal Close-packed (HCP) metals: Theory and MD simulations

“…The shear coupled motion of grain boundaries (GBs) is also modeled by both MD simulations (Ivanov and Mishin, 2008;Khater et al, 2012;Berbenni et al, 2013;Homer et al, 2013;Huang et al, 2014) and kinetic Monte Carlo (KMC) (Stukowski et al, 2014;Prieto-Depedro et al, 2015). MD and kinetic Monte Carlo (KMC) have successfully simulated other mechanisms in FCC or BCC metals (Junge and Molinari, 2014; Abdolrahim et al, 2014;Salehinia et al, 2014;Tucker and Foiles, 2014;Xiong et al, 2014;Yanilkin et al, 2014;Krasnikov and Mayer, 2015;Xu et al, 2015;Zhu et al, 2015;Kim et al, 2016). In order to mathematically model this uniaxial stress-driven GB migration in HCP metals, we employ an approach of the stability analysis on the interface diffusion controlled morphological 70 stability of lamellar microstructures (Sridhar et al, 1997;Song and Yang, 2008) at high temperatures.…”

Edge dislocations bowing out from a row of collinear obstacles in Al

“…Within each element, a finite element method with Gaussian quadrature is used to calculate the force/energy of the integration points and update the nodal positions, from which the positions of atoms inside the element are interpolated [27]. The coarse-grained description yields an accurate generalized stacking fault energy (GSFE) surface because the non-linear dislocation core structure/energy and Burgers vector are naturally accommodated [28].…”

“…The embedded-atom method (EAM) potential of Mishin et al [33] is adopted because the evaluated GSFE is close to the experimentally measured value [34]. The post-processing follows our earlier work [28,31], where more details of the CAC approach are given. Some runs are completed using Comet and Bridges on the NSF Extreme Science and Engineering Discovery Environment (XSEDE) [35].…”

“…Full atomistic resolution is applied in the vicinity of holes such that the hole surface is at least 2 nm from the atomistic/coarse-grained interface; away from the holes, 3D rhombohedral discontinuous elements with surfaces corresponding to {111} slip planes are employed [26]. Within each second nearest neighbor element, piecewise continuous first order shape and interpolation functions are used; between elements, neither displacement continuity nor interelement compatibility is required [28]. The lattice orientations are x½112 , y[110], and z½111.…”