Continuum Dislocation Dynamics Modeling of Mesoscale Crystal Plasticity at Finite Deformation

有限变形下介观晶体塑性的连续体位错动力学建模

• 批准号: 1663311
• 负责人: Anter El-Azab
• 金额: $ 43万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2022-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1663311&HistoricalAwards=false
• 关键词: Continuum; Dislocation; Dynamics; Modeling; Mesoscale

Mechanical deformation of crystalline metals is caused by motion and interactions of defects called dislocations under applied forces or stresses. As the individual crystals deform, dislocation interactions lead to the formation of self-organized dislocation microstructures or patterns. These patterns are believed to control the mechanical strength and failure of metals. They are also important in metal manufacturing as they provide the way to refine the material behavior through combined mechanical deformation and heating. Although dislocation patterns were observed long ago, there is currently no theoretical or computational framework for predicting their formation in metals under arbitrary deformation. This research aims to bridge this critical gap by implementing a computational modeling framework that explicitly represents dislocations and their interactions at the mesoscale based on the continuum dislocation dynamics method. Such a generalization will enable accurate prediction of material behavior in crystalline materials, and it will eventually lead to realistic models of the manufacturing processes of structural alloys. Scientific knowledge obtained in this research will be incorporated into graduate curriculum and the developed tools will be disseminated to the wider research community. A particular focus will be given to the training of female and underrepresented students through graduate research assistantships.The collective dislocation mechanisms that induce various dislocation microstructures in metal single crystals under deformation will be investigated by computational modeling. A recently developed computational framework based on continuum dislocation dynamics will be used as the method of investigation after generalization to finite crystal deformation. This modeling framework is theoretically founded to capture the full mesoscale deformation response of single crystals from dislocation properties, which includes the dislocation patterns, plastic slip distribution and crystal distortion, internal elastic fields, as well as the overall stress-strain response and average dislocation density evolution. The investigation includes the following research tasks: formulating the governing continuum dislocation dynamics equations at finite deformation and coupling these equations with the stress equilibrium and deformation kinematics of crystals, solving the coupled system of dislocation dynamics and crystal mechanics equations using the finite element approach, building a community available code for mesoscale deformation of crystals based on the above, and simulating the dislocation microstructures of interest and validating the predictions using open literature microstructure data obtained by Transmission Electron Microscopy and X-ray techniques.

晶体金属的机械变形是由称为位错的缺陷在施加的力或应力下的运动和相互作用引起的。当单个晶体变形时，位错相互作用导致自组织位错微观结构或图案的形成。这些图案被认为控制金属的机械强度和失效。它们在金属制造中也很重要，因为它们提供了通过机械变形和加热来改善材料性能的方法。虽然位错模式很久以前就被观察到了，但目前还没有理论或计算框架来预测它们在任意变形下在金属中的形成。本研究的目的是通过实施一个计算建模框架，明确表示位错及其相互作用的基础上连续位错动力学方法在中尺度上弥合这一关键差距。这样的概括将使晶体材料中的材料行为的准确预测，它最终将导致结构合金的制造过程的现实模型。在这项研究中获得的科学知识将被纳入研究生课程，开发的工具将传播到更广泛的研究界。通过研究生研究助学金，特别注重培养女性和代表性不足的学生。通过计算建模，研究在变形条件下金属单晶中诱发各种位错微观结构的集体位错机制。一个最近开发的计算框架的基础上连续位错动力学将被用来作为调查的方法后，推广到有限的晶体变形。该模型从理论上建立了一个完整的单晶体细观变形响应的位错特性模型，包括位错模式、塑性滑移分布和晶体变形、内部弹性场以及整体应力应变响应和平均位错密度演化。本次调查包括以下研究任务：建立了有限变形下的连续位错动力学方程，并将这些方程与晶体的应力平衡和变形运动学耦合起来，用有限元方法求解位错动力学和晶体力学方程的耦合系统，在此基础上建立了一个社区可用的晶体细观变形程序，以及模拟感兴趣的位错微观结构，并使用通过透射电子显微镜和X射线技术获得的公开文献微观结构数据来验证预测。

项目成果

On the computational solution of vector-density based continuum dislocation dynamics models: A comparison of two plastic distortion and stress update algorithms

• DOI: 10.1016/j.ijplas.2021.102943
• 发表时间: 2021-02
• 作者: P. Lin;Vignesh Vivekanandan;K. Starkey;B. Anglin;C. Geller;A. El-Azab

Theoretical development of continuum dislocation dynamics for finite-deformation crystal plasticity at the mesoscale

• DOI: 10.1016/j.jmps.2020.103926
• 发表时间: 2020-06
• 期刊: Journal of The Mechanics and Physics of Solids
• 影响因子: 5.3
• 作者: K. Starkey;G. Winther;A. El-Azab

Situating the Vector Density Approach Among Contemporary Continuum Theories of Dislocation Dynamics

将矢量密度方法置于当代位错动力学连续体理论中

• DOI: 10.1115/1.4052066
• 发表时间: 2022
• 期刊: Journal of engineering materials and technology
• 作者: Anderson, Joseph Pierre;Vivekanandan, Vignesh;Lin, Peng;Starkey, Kyle;Pachaury, Yash;El-Azab, Anter
• 通讯作者: El-Azab, Anter

Development of mean-field continuum dislocation kinematics with junction reactions using de Rham currents and graph theory

使用德拉姆电流和图论开发具有结反应的平均场连续位错运动学

• DOI: 10.1016/j.jmps.2021.104685
• 发表时间: 2022
• 期刊: Journal of the mechanics and physics of solids
• 影响因子: 5.3
• 作者: Starkey, Kyle;Hochrainer, Thomas;El-Azab, Anter
• 通讯作者: El-Azab, Anter

Impact of the plastic deformation microstructure in metals on the kinetics of recrystallization: A phase-field study

金属塑性变形微观结构对再结晶动力学的影响：相场研究

• DOI: 10.1016/j.actamat.2022.118332
• 发表时间: 2022
• 期刊: Acta materialia
• 影响因子: 9.4
• 作者: Hamed, Ahmed;Rayaprolu, Sreekar;Winther, Grethe;El-Azab, Anter
• 通讯作者: El-Azab, Anter