Equation of motion for dislocations with inertial effects
L. Pillon, C. Denoual, Y. -P. Pellegrini
提出了一个近似的运动运动方程的螺旋和刃位错，其中帐户的延迟和相对论效应在亚音速范围内。良好的定量协议被发现，在加速或减速制度，数值结果的更根本的性质。
An approximate equation of motion is proposed for screw and edge dislocations, which accounts for retardation and for relativistic effects in the subsonic range. Good quantitative agreement is found, in accelerated or in decelerated regimes, with numerical results of a more fundamental nature.
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A new formulation for the equation of motion of interacting dislocations is derived. From this solution it is shown that additional coupling forces, of kinetic and inertial origin, should be considered in Dislocation Dynamics (DD) simulations at high strain rates. A heuristic modification of this general equation of motion enables one to introduce retardation into inertial and elastic forces, in accordance with a progressive rearrangement of fields through wave propagation. The influence of the corresponding coupling terms and retardation effects are then illustrated in the case of dislocation…
Dislocation pinning plays a vital role in the plastic behaviour of a crystalline solid. Here we report the first observation of the damped oscillations of a mobile dislocation after it gets pinned at an obstacle in the presence of a constant static shear load. These oscillations are found to be inertial, instead of forced as obtained in the studies of internal friction of solid. The rate of damping enables us to determine the effective mass of the dislocation. Nevertheless, the observed relation between the oscillation frequency and the link length is found to be anomalous, when compared with …
Can vacancies lubricate dislocation motion in aluminum?
用半离散变分Peierls-Nabarro模型和从头算确定的γ面研究了Al中空位与位错的相互作用。首次从理论上证实了Al中位错运动的空位润滑效应，这一发现解决了面心立方金属位错理论中长期存在的争议。我们通过探索位错迁移率与其核心宽度之间的联系，提供了对润滑效应的见解。我们预测在空位的存在下位错分裂会增加。我们发现，平均而言，空位和位错之间存在一个与位错性质无关的弱排斥力。
Modes of Kink Motion on Dislocations in Semiconductors
分析了位错运动模式随应力和温度的变化。考虑了位错扭结对形成和扩展的不同状态（随机势中的运动、随机力场中的运动、准局部化）。讨论了位错速度的理论值与实验值之间的差异。
In this paper, we present a continuum model for the dynamics of low angle grain boundaries in two dimensions based on the motion of constituent dislocations of the grain boundaries. The continuum model consists of an equation for the motion of grain boundaries (i.e., motion of the constituent dislocations in the grain boundary normal direction) and equations for the dislocation structure evolution on the grain boundaries. This model is derived from the discrete dislocation dynamics model. The long-range elastic interaction between dislocations is included in the continuum model, which ensures …
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A phase field model of the effects of dislocation microstructure on grain boundary motion during recrystallization
本文提出了一种相场模型，用于研究位错微观结构对再结晶期间晶界运动的影响，通过模拟多尺度位错结构并对比实验结果，揭示了晶界运动的驱动机制。
Harnessing dislocation motion using an electric field
本研究首次实现仅通过外部电场控制单晶硫化锌中位错运动，发现带电30°部分位错因电场方向可逆移动而90°位错静止，为非机械场调制位错性质提供直接证据。
We develop a continuum model for the dynamics of grain boundaries in three dimensions that incorporates the motion and reaction of the constituent dislocations. The continuum model is based on a simple representation of densities of curved dislocations on the grain boundary. Illposedness due to nonconvexity of the total energy is fixed by a numerical treatment based on a projection method that maintains the connectivity of the constituent dislocations. An efficient simulation method is developed, in which the critical but computationally expensive long-range interaction of dislocations is repl…
Low temperature dynamics and kinetics of dislocation motion in the high-entropy alloy Al$_{0.5}$CoCrCuFeNi
本文通过塑性变形与声学弛豫分析，揭示了高熵合金Al$_{0.5}$CoCrCuFeNi中主导位错缺陷、势垒类型及室温和低温下的热激活运动机制，并基于现代位错理论给出了关键相互作用的定量估计。
We investigate the nonuniform motion of a straight screw dislocation in infinite media in the framework of the translational gauge theory of dislocations. The equations of motion are derived for an arbitrary moving screw dislocation. The fields of the elastic velocity, elastic distortion, dislocation density and dislocation current surrounding the arbitrarily moving screw dislocation are derived explicitely in the form of integral representations. We calculate the radiation fields and the fields depending on the dislocation velocities.
Lattice Resistance to Dislocation Motion at the Nanoscale
在这封信中，我们提出了一个模型，演示了在纳米系统中的移动位错所经历的晶格电阻的自由表面的效果。这种效应表现在由于位错线接近表面而提高的位错速度。为了验证这一发现，分子动力学模拟的bcc钼刃型位错进行，结果被发现是与该模型的数值实现。在较高的应力和温度下，这种效果的减少，如模拟所揭示的，证实了晶格电阻背后观察到的位错速度的变化的作用。
Thermally activated nature of synchro-Shockley dislocations in Laves phases
本研究针对Laves相中共格Shockley位错运动热激活本质不明的问题，探究不同应变水平下的跃迁机制，将事件分为剪切敏感与不敏感两类，明确了热激活对其运动的关键作用。
Unveiling the mechanisms of motion of synchro-Shockley dislocations in Laves phases
本研究通过原子模拟揭示Laves相中同步-肖克利位错的运动机制，发现扭结对形核传播及空位跳跃、间隙重排等关键过程，为理解塑性变形对温度和成分的依赖性提供见解。
A consistent, small scale description of plastic motion in a crystalline solid is presented based on a phase field description. By allowing for independent mass motion given by the phase field, and lattice distortion, the solid can remain in mechanical equilibrium on the timescale of plastic motion. Singular (incompatible) strains are determined by the phase field, to which smooth distortions are added to satisfy mechanical equilibrium. A numerical implementation of the model is presented, and used to study a benchmark problem: the motion of an edge dislocation dipole in a hexagonal lattice. T…
Linear complexions are defect phases that form in the presence of dislocations and thus are promising for the direct control of plasticity. In this study, atomistic simulations are used to model the effect of linear complexions on dislocation-based mechanisms for plasticity, demonstrating unique behaviors that differ from classical dislocation glide mechanisms. Linear complexions impart higher resistance to the initiation and continuation of dislocation motion when compared to solid solution strengthening in all of the face-centered cubic alloys investigated here, with the exact strengthening …
A number of recent Molecular Dynamics (MD) simulations have demonstrated that screw dislocations in face centered cubic (fcc) metals can achieve stable steady state motion above the lowest shear wave speed ($v_\text{shear}$) which is parallel to their direction of motion (often referred to as transonic motion). This is in direct contrast to classical continuum analyses which predict a divergence in the elastic energy of the host material at a crystal geometry dependent `critical' velocity $v_\text{crit}$. Within this work, we first demonstrate through analytic analyses that the elastic energy …
Discrete models of dislocations and their motion in cubic crystals
本文提出了一个以标准线性各向异性弹性为连续极限的、描述晶格缺陷的离散模型。进入模型的主要成分是材料的弹性刚度常数和一个无量纲的周期函数，恢复晶体的平移不变性和影响Peierls应力。给出了立方对称晶体：sc，fcc和bcc的显式表达式。该模型的数值模拟与保守或阻尼动力学说明静态和移动刃和螺旋位错，并描述他们的核心和配置文件。位错环和偶极子也进行了数值观察。裂纹可以通过向由两个刃位错形成的偶极子施加足够的载荷来产生和扩展。
Fluctuation - induced nucleation and dynamics of the kinks on dislocation. Soliton and oscillation regimes in 2D Frenkel-Kontorova model
对二维Frenkel-Kontorova（FK）模型中位错在恒温器中的运动进行了数值模拟，发现了一种不寻常的动力学行为。位错滑移的“扭折”区出现在模型参数的一定范围内，但与通常关于塑性形变条件下位错运动的观点不同，尽管晶格、阻尼和热涨落是离散的，但扭折区类似于sine-Gordon孤子。在足够高的应力和温度下，位错的运动伴随着它的振荡而不是扭结形核。
The aim of this paper is to provide new results and insights for a screw dislocation in functionally graded media within the gauge theory of dislocations. We present the equations of motion for dislocations in inhomogeneous media. We specify the equations of motion for a screw dislocation in a functionally graded material. The material properties are assumed to vary exponentially along the x and y-directions. In the present work we give the analytical gauge field theoretic solution to the problem of a screw dislocation in inhomogeneous media. Using the dislocation gauge approach, rigorous anal…
A novel implementation of the dislocation flux boundary condition in discrete dislocation dynamics is presented. The continuity of the individual dislocation loops in a periodic representative crystal volume (RVE) is enforced across the boundary of the RVE with the help of a dual topological description for representing dislocation line kinematics in two equivalent spaces representing the deforming crystal, the RVE and the unbounded crystal spaces. The former describes the motion of the dislocations in the simulated crystal RVE whereas the latter represents the motion of dislocations in an inf…
Isolated kinks on thermally fluctuating (1/2)<111> screw, <100> edge and (1/2)<111> edge dislocations in bcc iron are simulated under zero stress conditions using molecular dynamics (MD). Kinks are seen to perform stochastic motion in a potential landscape that depends on the dislocation character and geometry, and their motion provides fresh insight into the coupling of dislocations to a heat bath. The kink formation energy, migration barrier and friction parameter are deduced from the simulations. A discrete Frenkel-Kontorova-Langevin (FKL) model is able to reproduce the coarse grained data …
A small-distortion geometric model for elasto-plasticity in single crystals driven by the motion of dislocations
本文提出小畸变几何模型，基于小畸变假设与线张力近似，结合时空框架，实现由位错运动直接驱动的单晶弹塑性建模，并连接离散位错与连续介质理论。
Building on ideas introduced by Eshelby in 1953, and on recent dynamical extensions of the Peierls model for screw and edge dislocations, an approximate equation of motion (EoM) to govern non-uniform dislocation motion under time-varying stress is derived, allowing for time variations of the core width. Non-local in time, it accounts for radiative visco-inertial effects and non-radiative drag. It is completely determined by energy functions computed at constant velocity. Various limits are examined, including that of vanishing core width. Known results are retrieved as particular cases. Notabl…
A three-dimensional continuum dislocation theory for single crystals containing curved dislocations is proposed. A set of governing equations and boundary conditions is derived for the true placement, plastic slips, and loop functions in equilibrium that minimize the free energy of crystal among all admissible functions, provided the resistance to the dislocation motion is negligible. For the non-vanishing resistance to dislocation motion the governing equations are derived from the variational equation that includes the dissipation function. A simplified theory for small strains is also provi…
Excitation of normal modes of a thin elastic plate by moving dislocations
本文研究了薄弹性样品中任意运动的单个位错激发的谐波。我们考虑垂直于层表面运动的螺位错和刃位错。在傅立叶空间中，位错运动产生的位移速度和动态应力场被分解为两项的乘积：一项仅取决于位错的运动，而另一项与位错的运动无关，并代表介质的响应。后一项在满足板的谐波模式的色散关系的频率处具有极点。在螺旋位错的情况下，被激发的模式是反对称瑞利-兰姆模式的一个子族。对于刃型位错的对称瑞利-兰姆模式的一个子家族的激发，以及最低的躺剪切模式。详细推导了匀速运动螺旋的表达式，当速度与允许模式的相速度一致时，该表达式具有奇异性。
Interactions among dislocations and solute atoms are the basis of several important processes in metals plasticity. In body-centered cubic (bcc) metals and alloys, low-temperature plastic flow is controlled by screw dislocation glide, which is known to take place by the nucleation and sideward relaxation of kink pairs across two consecutive \emph{Peierls} valleys. In alloys, dislocations and solutes affect each other's kinetics via long-range stress field coupling and short-range inelastic interactions. It is known that in certain substitutional bcc alloys a transition from solute softening to…
Transonic Dislocation Propagation in Diamond
针对位错最大运动速度未明确的问题，研究采用飞秒X射线成像追踪冲击压缩单晶金刚石的超快速位错，通过观测快于最慢声速的堆垛层错，证实部分位错可跨音速运动，为极端条件材料力学性能研究提供关键依据。
Quantum motion of atoms known as zero-point vibrations is recognized to be important at low temperatures in condensed matter systems comprised of light atoms or ions, affecting such properties and behaviors as proton-transfer reactions, vibrational spectra of water and ice, and mechanical properties of low temperature helium. Recently, quantum motion of atoms was proposed to explain a long-standing discrepancy between theoretically computed and experimentally measured low-temperature resistance (Peierls stress) to dislocation motion in iron and possibly other metals with high atomic masses. He…
The stress-driven motion of dislocations in crystalline solids, and thus the ensuing plastic deformation process, is greatly influenced by the presence or absence of various point-like defects such as precipitates or solute atoms. These defects act as obstacles for dislocation motion and hence affect the mechanical properties of the material. Here we combine molecular dynamics studies with three-dimensional discrete dislocation dynamics simulations in order to model the interaction between different kinds of precipitates and a $\frac{1}{2}\langle 1 1 1\rangle$ $\{1 1 0\}$ edge dislocation in B…
Dislocation dynamics in Ni-based superalloys: Parameterising dislocation trajectories from atomistic simulations
本研究利用纯镍分子动力学轨迹，通过 DE-MC 方法标定带不确定性的位错运动方程参数，为镍基高温合金变形代理模型奠定基础。
Dislocations in single-phase concentrated random alloys, including high- entropy alloys (HEAs), repeatedly encounter pinning during glide, resulting in jerky dislocation motion. While solute-dislocation interaction is well understood in conventional alloys, the origin of individual pinning points in concentrated random alloys is a matter of debate. In this work, we investigate the origin of dislocation pinning in the CoCrFeMnNi HEA. In- situ transmission electron microscopy studies reveal wavy dislocation lines and a jagged glide motion under external loading, even though no segregation or clu…
Enhanced mobility of dislocation network nodes and its effect on dislocation multiplication and strain hardening
本文通过对比MD与DDD模拟，发现BCC晶体中位错网络节点具有此前未知的运动自由度，将其纳入DDD后可显著改善对位错增殖、回复和存储及应变硬化的预测。
In this paper we present the equations of motion of a moving screw dislocation in the framework of the translation gauge theory of dislocations. In the gauge field theoretical formulation, a dislocation is a massive gauge field. We calculate the gauge field theoretical solutions of a uniformly moving screw dislocation. We give the subsonic and supersonic solutions. Thus, supersonic dislocations are not forbidden from the field theoretical point of view. We show that the elastic divergences at the dislocation core are removed. We also discuss the Mach cones produced by supersonic screw dislocat…
Crystal plasticity is the result of the motion and interaction of dislocations. There is, however, still a major gap between microscopic and mesoscopic simulations and continuum crystal plasticity models. Only recently a higher dimensional dislocation density tensor was defined which overcomes some drawbacks of earlier dislocation density measures. The evolution equation for this tensor can be considered as a continuum version of dislocation dynamics. We use this evolution equation to develop evolution equations for the total dislocation density and an average curvature which together govern a…
Quantitative study of the pinning effect of the edge dislocation on domain wall motion in Barium Titanate thin films
本研究提出一种通过界面本征应变实现刃型位错的相场模型，定量分析了钛酸钡薄膜中位错对畴壁运动及电滞回线的钉扎效应，揭示了外部载荷与Burgers矢量大小之间的竞争关系。
A phase field model of a crystalline material at the mesoscale is introduced to develop the necessary theoretical framework to study plastic flow due to dislocation motion. We first obtain the elastic stress from the phase field free energy and show that it obeys the stress strain relation of linear elasticity. Dislocations in a two dimensional hexagonal lattice are shown to be composite topological defects in the amplitude expansion of the phase field, with topological charges given by the Burgers vector. This allows us to introduce a formal relation between dislocation velocity and the evolu…
Properties of accelerating edge dislocations in arbitrary slip systems with reflection symmetry
本文研究具有反射对称性的任意滑移系中加速刃位错的理论解，为理解高速位错运动、跨声速位错速度是否存在及晶体高速率塑性变形提供基础。
The purpose of this paper is the fundamental theory of the non-uniform motion of dislocations in two and three space-dimensions. We investigate the non-uniform motion of an arbitrary distribution of dislocations, a dislocation loop and straight dislocations in infinite media using the theory of incompatible elastodynamics. The equations of motion are derived for non-uniformly moving dislocations. The retarded elastic fields produced by a distribution of dislocations and the retarded dislocation tensor potentials are determined. New fundamental key-formulae for the dynamics of dislocations are …
Compression experiments on micron-scale specimens and acoustic emission (AE) measurements on bulk samples revealed that the dislocation motion resembles a stick-slip process - a series of unpredictable local strain bursts with a scale-free size distribution. Here we present a unique experimental set-up, which detects weak AE waves of dislocation slip during the compression of Zn micropillars. Profound correlation is observed between the energies of deformation events and the emitted AE signals that, as we conclude, are induced by the collective dissipative motion of dislocations. The AE data a…
The interaction between screw dislocations and oxygen interstitial atoms is studied with ab initio calculations in hexagonal close-packed titanium. Our calculations evidence a strong repulsion when the solute atoms are located in the dislocation glide plane, leading to spontaneous cross-slip, which allows the dislocation to bypass the atomic obstacle. This avoidance process explains several experimental observations in titanium in presence of oxygen: (1) a larger lattice friction against screw dislocation motion, (2) a reduction of the dislocation glide distance in prismatic planes and (3) an …
New features of dislocation structures arising from lattice discreteness
晶格和位错结构之间的关系的新方面进行检查在一个物理上透明的理论方案。源自晶格离散性的预测特征包括：（i）多个核心位错结构和（ii）它们对位错轴位置的依赖性。这些效应，原则上可以直接观察到，也可以表现在位错运动或/和转变（交叉滑移）特性中，是非常普遍的，存在于任何晶体中，它们可能或多或少地明显，这取决于材料。
Effect of Anisotropic Peierls Barrier on the Evolution of Discrete Dislocation Networks in Ni
本研究通过离散位错动力学模拟，揭示了Peierls应力各向异性对Ni单晶位错网络演化的影响，发现其提高硬化速率和网络连通性，但抑制近螺型位错段的运动。
Ab Initio Study of Screw Dislocations in Mo and Ta: A new picture of plasticity in bcc transition metals
我们首次报道了<111>体心立方过渡金属Mo和Ta中螺位错核的从头计算密度泛函研究。我们的研究结果提出了一个新的图片的体心立方塑性对称和紧凑的位错核心，相反，目前接受的图片的基础上连续和原子间的潜力。在这个新的图片的核心能量尺度是在更好地符合Peierls能量障碍位错运动的实验建议。
The present paper extends the thermodynamic dislocation theory initiated by Langer, Bouchbinder and Lookman [2010] to non-uniform finite plastic deformations. The equations of motion are derived from the variational equation involving the free energy density and the positive definite dissipation function. We also consider the simplified theory by neglecting the excess dislocations. For illustration, the problem of finite strain constrained shear of single crystals with one active slip system is solved within the proposed theory.
In this work we investigate the theory of dynamics of dislocations in quasicrystals. We consider three models: the elastodynamic model of wave type, the elasto-hydrodynamic model, and the elastodynamic model of wave-telegraph type. Similarities and differences between the three models are pointed out and discussed. Using the framework of linear incompatible elastodynamic theory, the equations of motion of dislocations are deduced for these three models. Especially, the equations of motion for the phonon and phason elastic distortion tensors and elastic velocity vectors are derived, where the s…
Thermally-activated $\small{\nicefrac{1}{2}}<111>$ screw dislocation motion is the controlling plastic mechanism at low temperatures in body-centered cubic (bcc) crystals. Motion proceeds by the nucleation and propagation of atomic-sized kink pairs susceptible of being studied using molecular dynamics (MD). However, MD's natural inability to properly sample thermally-activated processes as well as to capture $\{110\}$ screw dislocation glide calls for the development of other methods capable of overcoming these limitations. Here we develop a kinetic Monte Carlo (kMC) approach to study single s…
Plastic deformation of crystals is a physical phenomenon, which has immensely driven the development of human civilisation since the onset of the Chalcolithic period. This process is primarily governed by the motion of line defects, called dislocations. Each dislocation traps a quantum of plastic deformation expressible in terms of its Burgers vector[1,2]. Theorising the mechanisms of dislocation motion at the atomistic scales of length and time remains a challenging task on account of the extreme complexities associated with the dynamics. We present a new concept of modelling a moving disloca…
Dislocation interactions mediated by grain boundaries
变形晶体中位错集合的动力学表明了集体现象、间歇波动和应变雪崩的出现。在多晶材料中，对塑性形变机制的理解取决于对晶界在位错运动中的作用的把握。在这里的位错和弹性，低角度晶界的相互作用进行了研究的离散位错表示的框架。我们允许晶界变形的位错应力场的影响下，并比较这样的扰动刚性晶粒bouches的情况下的效果。我们能够确定，无论是分析和数值，修正位错应力场作用于相邻的晶粒，介导的晶界变形。最后，我们讨论的雪崩统计的结论和后果，在多晶样品中观察到的。
Fluctuation depinning of the dislocation kink under the influence of external forces
在McLaughlin-Scott微扰理论的框架内的位错扭结在钉扎电位的运动方程线性化，假设同时影响的交流和直流力。在此基础上，研究了扭结脱钉的概率。详细分析了脱钉概率对直流力和交流力的依赖关系。
A continuum model of the two dimensional low angle grain boundary motion and the dislocation structure evolution on the grain boundaries has been developed in Ref. [48]. The model is based on the motion and reaction of the constituent dislocations of the grain boundaries. The long-range elastic interaction between dislocations is included in the continuum model, and it maintains a stable dislocation structure described by the Frank's formula for grain boundaries. In this paper, we develop a new continuum model for the coupling and sliding motions of grain boundaries that avoids the time-consum…
The action functional for a linear elastic medium with dislocations is given. The equations of motion following from this action reproduce the Peach-Köhler and Lorentzian forces experienced by dislocations. The explicit expressions for singular and finite parts of the self-force acting on a curved dislocation are derived in the framework of linear theory of elasticity of an isotropic medium. The velocity of dislocation is assumed to be arbitrary but less than the shear wave velocity. The slow speed and near-sonic motions of a dislocation are investigated. In the near-sonic limit, the explicit …
We introduce a phenomenological theory of dislocation motion appropriate for two dimensional lattices. A coarse grained description is proposed that involves as primitive variables local lattice rotation and Burgers vector densities along distinguished slip systems of the lattice. We then use symmetry considerations to propose phenomenological equations for both defect energies and their dissipative motion. As a consequence, the model includes explicit dependences on the local state of lattice orientation, and allows for differential defect mobilities along distinguished directions. Defect den…
The classical motion of gliding dislocation lines in slip planes of crystalline solid helium leads to plastic deformation even at temperatures far below the Debye temperature and can affect elastic properties. In this work we argue that the gliding of dislocations and plasticity may be the origin of many observed elastic anomalies in solid He-4, which have been argued to be connected to supersolidity. We present a dislocation motion model that describes the stress-strain $τ$-$ε$ curves and work hardening rate $dτ/dε$ of a shear experiment performed at constant strain rate $\dotε$ in solid heli…
Unlike the tensile mode, compressive deformation of a bcc metallic nanostructure is mediated by the glide of screw dislocation. Although the bcc screw dislocations are well known to possess unusual attributes, it is still unclear how these unique effects manifest in a nanoscale solid. In the present study, atomistic simulations render a close look at the dislocation activities underlying the compressive deformation of bcc iron nanopillars. It is found that instead of performing simple glide motion, the line defects exhibit a host of complex features. In this regard, the temperature is observed…
High-entropy alloys (HEAs) with concentrated solid solutions are conceived to possess a rugged atomic and energy landscape in which dislocation motion necessarily proceeds to accommodate mechanical deformation. Fundamental questions remain as to how rough the energy landscape is and to what extent it can be influenced by the local ordering of their constituent elements. Here, we construct and report the potential energy landscape (PEL) governing screw dislocation motion in refractory HEAs that reveals a hierarchical and multilevel structure with a collection of small basins nested in large met…
A theoretical framework is proposed to derive a dynamic equation motion for rectilinear dislocations within isotropic continuum elastodynamics. The theory relies on a recent dynamic extension of the Peierls-Nabarro equation, so as to account for core-width generalized stacking-fault energy effects. The degrees of freedom of the solution of the latter equation are reduced by means of the collective-variable method, well known in soliton theory, which we reformulate in a way suitable to the problem at hand. Through these means, two coupled governing equations for the dislocation position and cor…
Plasticity in hexagonal close-packed zirconium is controlled by screw dislocations which easily glide in the prismatic planes where they are dissociated. At high enough temperatures, these dislocations can deviate out of the prism planes to also glide in the first order pyramidal and basal planes. To get a better understanding of these secondary slip systems, we have performed molecular dynamics (MD) simulations of a screw dislocation gliding in a basal plane. The gliding dislocation remains dissociated in the prism plane where it performs a random motion and occasionally cross-slips out of it…
Size-Dependent Power Laws for Edge Dislocations in Nickel Superalloys: A Molecular Dynamics Study
本文利用分子动力学模拟研究了镍高温合金中刃型位错运动的临界分切应力尺寸效应，发现CRSS对γ'析出相体积分数呈双区域幂律依赖，并归结为CRSS对析出相长度的线性关系，临界转变尺度为成对位错总核心宽度。
Dislocations are a central concept in materials science, which dictate the plastic deformation and damage evolution in materials. Layered materials such as graphite admit two general types of interlayer dislocations: basal and prismatic dislocations, of which prismatic dislocations have been relatively less studied. Using density functional theory (DFT) calculations, we have examined different prismatic core structures in graphite and evaluated their structure, energetics and mobility. We find close energetic interplay between bonded and "free-standing" core structures in both zigzag and armch…
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