Materials Theory最新文献_第6页

The Green tensor of Mindlin’s anisotropic first strain gradient elasticity 闵德林各向异性第一应变梯度弹性的格林张量

Materials Theory Pub Date : 2019-03-15 DOI: 10.1186/s41313-019-0015-2

Giacomo Po, Nikhil Chandra Admal, Markus Lazar

引用次数: 11

GD3: generalized discrete defect dynamics GD3:广义离散缺陷动力学

Materials Theory Pub Date : 2019-01-31 DOI: 10.1186/s41313-018-0013-9

Laurent Capolungo, Vincent Taupin

{"title":"GD3: generalized discrete defect dynamics","authors":"Laurent Capolungo, Vincent Taupin","doi":"10.1186/s41313-018-0013-9","DOIUrl":"https://doi.org/10.1186/s41313-018-0013-9","url":null,"abstract":"A mesoscale model is introduced to study the dynamics of material defects lying at interface junctions. The proposed framework couples the dynamics of discrete dislocation and disclination lines. Disclinations are expected to be natural defects at interface junctions; their presence serving the purpose of accommodating discontinuities in rotation fields at material interface junctions. Crystallography-based rules are proposed to describe the kinematics of disclination motion. A discrete-continuous couple-stress framework, in which discrete defect lines are introduced as plastic eigenstrains and eigencurvatures, is proposed to explicitly follow the dynamics of interfacial defects. The framework is then applied to study (left (10bar {1}2right)) twin transverse propagation and thickening in magnesium. Focusing first on the case of a twin domain, It is shown that a disclination based representation of twin domains allows for an appropriate mechanistic description of the kinematics of shear transformations. In what concerns twin thickening, the stability of defects at twin interfaces is further studied. To this end, a 3D crater lying on a twin interface is described as a dipole of disclination loops. Upon self-relaxation, it is found that out of plane motion of disclinations followed by the nucleation of twinning dislocations can be activated; thereby showing that conservative non-planar motion of disclinations can be thermodynamically favorable; mechanism that had been postulated some 50 years ago.","PeriodicalId":693,"journal":{"name":"Materials Theory","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s41313-018-0013-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5179932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 14

Thermodynamic considerations of same-metal electrodes in an asymmetric cell 不对称电池中同金属电极的热力学考虑

Materials Theory Pub Date : 2019-01-25 DOI: 10.1186/s41313-018-0014-8

M. H. Braga, N. S. Grundish, A. J. Murchison, J. B. Goodenough

{"title":"Thermodynamic considerations of same-metal electrodes in an asymmetric cell","authors":"M. H. Braga, N. S. Grundish, A. J. Murchison, J. B. Goodenough","doi":"10.1186/s41313-018-0014-8","DOIUrl":"https://doi.org/10.1186/s41313-018-0014-8","url":null,"abstract":"An electrochemical cell contains three open thermodynamic systems that, in dynamic equilibrium, equalize their electrochemical potentials with that of their surrounding by forming an electric-double-layer-capacitor at the interface of the electrolyte with each of the two electrodes. Since the electrode/electrolyte interfaces are heterojunctions, the electrochemical potentials or Fermi levels of the two materials that contact the electrolyte at the two electrodes determine the voltage of a cell. The voltage is the sum of the voltages of the two interfacial electric-double-layer capacitors at the two electrode/electrolyte interfaces. A theoretical analysis of the thermodynamics that gives a quantitative prediction of the observed voltages in an asymmetric cell with an S8 relay at the positive electrode is provided. In addition, new discharge data and an X-ray photoelectron spectroscopy analysis of the lithium plated on the positive electrode of a discharged cell is presented. Ab initio, DFT methods were used to calculate the band structure and surface-state energies of the crystalline S8 solid sulfur relay. The theoretical exposition of the thermodynamics of the operative driving force of the chemical reactions in an electrochemical cell demonstrate that our initial experimental data and conclusions are valid. Other reported observations of lithium plating on the positive electrode, observations that were neither exploited nor their origins specified, are also cited.","PeriodicalId":693,"journal":{"name":"Materials Theory","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s41313-018-0014-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4965522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

“Irregularization” of systems of conservation laws 守恒定律系统的“非规则化”

Materials Theory Pub Date : 2018-08-15 DOI: 10.1186/s41313-018-0012-x

Hunter Swan, Woosong Choi, Stefanos Papanikolaou, Matthew Bierbaum, Yong S. Chen, James P. Sethna

引用次数: 1

Mixed-mode growth of a multicomponent precipitate in the quasi-steady state regime 准稳态下多组分析出物的混合模式生长

Materials Theory Pub Date : 2018-05-23 DOI: 10.1186/s41313-018-0011-y

Tohid Naseri, Daniel Larouche, Rémi Martinez, Francis Breton

{"title":"Mixed-mode growth of a multicomponent precipitate in the quasi-steady state regime","authors":"Tohid Naseri, Daniel Larouche, Rémi Martinez, Francis Breton","doi":"10.1186/s41313-018-0011-y","DOIUrl":"https://doi.org/10.1186/s41313-018-0011-y","url":null,"abstract":"An exact analytical solution of the Fick’s second law was developed and applied to the mixed-mode growth of a multicomponent ellipsoidal precipitate growing with constant eccentricities in the quasi-stationary regime. The solution is exact if the nominal composition, equilibrium concentrations and material properties are assumed constant, and can be applied to compounds having no limitations in the number of components. The solution was compared to the solution calculated by a diffusion-controlled application software and it was found that the solute concentrations at the interface can be determined knowing only the nominal composition, the full equilibrium concentrations and the coefficients of diffusion. The thermodynamic calculations owing to find alternative tie-lines are proven to be useless in the mixed-mode model. From this, it appears that the search of alternative tie-lines is computationally counterproductive, even when the interface has a very high mobility. A more efficient computational scheme is possible by considering that a moving interface is not at equilibrium.","PeriodicalId":693,"journal":{"name":"Materials Theory","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s41313-018-0011-y","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4903963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Annihilation and sources in continuum dislocation dynamics 连续位错动力学中的湮灭与源

Materials Theory Pub Date : 2018-03-20 DOI: 10.1186/s41313-018-0010-z

Mehran Monavari, Michael Zaiser

引用次数: 28

An analysis of two classes of phase field models for void growth and coarsening in irradiated crystalline solids 辐照结晶固体中孔洞生长和粗化的两类相场模型分析

Materials Theory Pub Date : 2018-01-31 DOI: 10.1186/s41313-017-0008-y

K. Ahmed, A. El-Azab

{"title":"An analysis of two classes of phase field models for void growth and coarsening in irradiated crystalline solids","authors":"K. Ahmed, A. El-Azab","doi":"10.1186/s41313-017-0008-y","DOIUrl":"https://doi.org/10.1186/s41313-017-0008-y","url":null,"abstract":"A formal asymptotic analysis of two classes of phase field models for void growth and coarsening in irradiated solids has been performed to assess their sharp-interface kinetics. It was found that the sharp interface limit of type B models, which include only point defect concentrations as order parameters governed by Cahn-Hilliard equations, captures diffusion-controlled kinetics. It was also found that a type B model reduces to a generalized one-sided classical Stefan problem in the case of a high driving thermodynamic force associated with the void growth stage, while it reduces to a generalized one-sided Mullins-Sekerka problem when the driving force is low in the case of void coarsening. The latter case corresponds to the famous rate theory description of void growth. Type C models, which include point defect concentrations and a non-conserved order parameter to distinguish between the void and solid phases and employ coupled Cahn-Hilliard and Allen-Cahn equations, are shown to represent mixed diffusion and interfacial kinetics. In particular, the Allen-Cahn equation of model C reduces to an interfacial constitutive law representing the attachment and emission kinetics of point defects at the void surface. In the limit of a high driving force associated with the void growth stage, a type C model reduces to a generalized one-sided Stefan problem with kinetic drag. In the limit of low driving forces characterizing the void coarsening stage, however, the model reduces to a generalized one-sided Mullins-Sekerka problem with kinetic drag. The analysis presented here paves the way for constructing quantitative phase field models for the irradiation-driven nucleation and growth of voids in crystalline solids by matching these models to a recently developed sharp interface theory.","PeriodicalId":693,"journal":{"name":"Materials Theory","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s41313-017-0008-y","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5175447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 12

Determining Cosserat constants of 2D cellular solids from beam models 从梁模型中确定二维细胞固体的Cosserat常数

Materials Theory Pub Date : 2018-01-31 DOI: 10.1186/s41313-017-0009-x

Stefan Liebenstein, Michael Zaiser

{"title":"Determining Cosserat constants of 2D cellular solids from beam models","authors":"Stefan Liebenstein, Michael Zaiser","doi":"10.1186/s41313-017-0009-x","DOIUrl":"https://doi.org/10.1186/s41313-017-0009-x","url":null,"abstract":"We present results of a two-scale model of disordered cellular materials where we describe the microstructure in an idealized manner using a beam network model and then make a transition to a Cosserat-type continuum model describing the same material on the macroscopic scale. In such scale transitions, normally either bottom-up homogenization approaches or top-down reverse modeling strategies are used in order to match the macro-scale Cosserat continuum to the micro-scale beam network. Here we use a different approach that is based on an energetically consistent continuization scheme that uses data from the beam network model in order to determine continuous stress and strain variables in a set of control volumes defined on the scale of the individual microstructure elements (cells) in such a manner that they form a continuous tessellation of the material domain. Stresses and strains are determined independently in all control volumes, and constitutive parameters are obtained from the ensemble of control volume data using a least-square error criterion. We show that this approach yields material parameters that are for regular honeycomb structures in close agreement with analytical results. For strongly disordered cellular structures, the thus parametrized Cosserat continuum produces results that reproduce the behavior of the micro-scale beam models both in view of the observed strain patterns and in view of the macroscopic response, including its size dependence.","PeriodicalId":693,"journal":{"name":"Materials Theory","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s41313-017-0009-x","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5174366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 15

Erratum to: a novel model of third phase inclusions on two phase boundaries 对两相边界上的第三相包裹体新模型的勘误

Materials Theory Pub Date : 2017-07-28 DOI: 10.1186/s41313-017-0007-z

Andrew A. Prudil, Michael J. Welland

引用次数: 1

Diffuse-interface polycrystal plasticity: expressing grain boundaries as geometrically necessary dislocations 扩散界面多晶塑性:将晶界表示为几何上必要的位错

Materials Theory Pub Date : 2017-07-11 DOI: 10.1186/s41313-017-0006-0

Nikhil Chandra Admal, Giacomo Po, Jaime Marian

{"title":"Diffuse-interface polycrystal plasticity: expressing grain boundaries as geometrically necessary dislocations","authors":"Nikhil Chandra Admal, Giacomo Po, Jaime Marian","doi":"10.1186/s41313-017-0006-0","DOIUrl":"https://doi.org/10.1186/s41313-017-0006-0","url":null,"abstract":"The standard way of modeling plasticity in polycrystals is by using the crystal plasticity model for single crystals in each grain, and imposing suitable traction and slip boundary conditions across grain boundaries. In this fashion, the system is modeled as a collection of boundary-value problems with matching boundary conditions. In this paper, we develop a diffuse-interface crystal plasticity model for polycrystalline materials that results in a single boundary-value problem with a single crystal as the reference configuration. Using a multiplicative decomposition of the deformation gradient into lattice and plastic parts, i.e. F(X,t)=F\u0000 L(X,t)F\u0000 P(X,t), an initial stress-free polycrystal is constructed by imposing F\u0000 L to be a piecewise constant rotation field R\u0000 0(X), and F\u0000 P=R\u0000 0(X)T, thereby having F(X,0)=I, and zero elastic strain. This model serves as a precursor to higher order crystal plasticity models with grain boundary energy and evolution.","PeriodicalId":693,"journal":{"name":"Materials Theory","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s41313-017-0006-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4456768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8