CAREER: Constrained Slip, Cracking and Instability in Extremely Anisotropic Nanolayered Solids

职业：极端​​各向异性纳米层固体中的约束滑移、开裂和不稳定性

• 批准号: 1944496
• 负责人: Ankit Srivastava
• 金额: $ 50.75万
• 依托单位: Texas A&M Engineering Experiment Station
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1944496&HistoricalAwards=false
• 关键词: CAREER; Constrained; Slip; Cracking; Instability

This Faculty Early Career Development (CAREER) grant will focus on quantifying the effects of microstructural deformation mechanisms on the mechanical response of materials with nanolayered crystal structures, such as zinc, mica, and certain carbides. These materials hold tremendous promise for technologies where reliable performance is required under extreme environments, such as at elevated temperatures. However, their use in critical applications is severely limited as they exhibit extremely direction-dependent (anisotropic) behavior, cannot accommodate an arbitrary shape change, and are essentially brittle. On the other hand, the anisotropy of these materials enables them to undergo macroscale deformation via crystal slip, cracking, and/or instability at smaller scales, which in turn can significantly enhance their damage tolerance and ductility. This research project will provide the fundamental understanding of the microstructure-based mechanical response of nanolayered crystalline materials, paving the possibility of microstructural engineering to harness their damage tolerance and ductility for applications. This objective will be achieved with an integrated experimental-computational approach, which will result in a predictive modeling framework and experimental data at several length scales. The research activities will be complemented with a series of fully integrated educational and outreach activities. The educational activities will enhance undergraduate and graduate level engineering education through development of interactive instructional materials and a new course. The outreach activities will increase awareness of engineering by engaging Texas high school teachers in research and students in a summer camp, respectively.The objective of this research is twofold. First, develop an understanding of the synergistic effects of crystallographic slip, cracking, and instability in extremely anisotropic nanolayered materials, oxides, carbides and nitrides, via novel small-scale in-situ experiments. Second, develop and validate a crystal plasticity-based constitutive model incorporating non-Schmid effects, cleavage-like cracking, and local instability to predict microstructure-sensitive mechanical response of these materials. This will provide answers to following key fundamental questions: (i) What material property or a combination of properties affect the onset and propagation of slip, cracking and instability in single crystals? (ii) What are the synergistic effects of slip, cracking and instability on overall plastic deformation and damage tolerance? (iii) What is the role of non-Schmid effects on the onset of cracking and instability? (iv) How does intergranular cracking affect the damage tolerance of polycrystals of these materials?This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

这项教师早期职业发展（职业）赠款将重点放在量化微结构变形机制对具有纳米晶体结构（例如锌，云母和某些碳化物）材料机械响应的影响。这些材料对在极端环境（例如温度升高时）需要可靠的性能的技术具有巨大的希望。但是，它们在关键应用中的使用受到严重限制，因为它们表现出极度依赖于方向的行为（各向异性）行为，无法适应任意形状的变化，并且本质上是脆弱的。另一方面，这些材料的各向异性使它们能够在较小的尺度下通过晶体滑动，裂纹和/或不稳定性进行宏观的变形，进而可以显着增强其损伤的耐受性和延展性。该研究项目将提供对基于微结构的纳光晶体材料的机械响应的基本理解，从而铺平了微观结构工程的可能性，以利用其对应用的损伤耐受性和延展性。通过集成的实验计算方法将实现这一目标，这将在几个长度尺度上产生预测的建模框架和实验数据。研究活动将与一系列完全整合的教育和外展活动相辅相成。教育活动将通过开发互动教学材料和新课程来增强本科和研究生水平的工程教育。外展活动将分别与得克萨斯高中教师参与夏季训练营的研究和学生，从而提高对工程的认识。这项研究的目标是双重的。首先，通过新型的小型现场实验，对极度各向异性纳米层的材料，氧化物，碳化物和氮化物进行了晶体学滑移，开裂和不稳定性的协同作用的理解。其次，开发和验证了基于晶体可塑性的本构模型，该模型融合了非schmid效应，裂解样的裂纹以及局部不稳定性，以预测这些材料的微结构敏感机械响应。这将为以下关键基本问题提供答案：（i）单晶中有哪些材料特性或属性组合会影响滑移，破裂和不稳定性的发作和传播？ （ii）滑动，破裂和不稳定性对整体塑性变形和损伤耐受性有什么协同作用？ （iii）非SCHMID对裂纹和不稳定性的发作的作用是什么？ （iv）晶间开裂如何影响这些材料多晶的损害耐受性？该奖项反映了NSF的法定任务，并且使用基金会的知识分子优点和更广泛的影响审查标准，被认为值得通过评估来获得支持。

项目成果

Modeling the non-Schmid crystallographic slip in MAX phases

• DOI: 10.1016/j.ijplas.2022.103399
• 发表时间: 2022-08
• 期刊: International Journal of Plasticity
• 影响因子: 9.8
• 作者: U. Asim;Zhiqiang Zhan;M. Radovic;A. Srivastava

On the non-classical crystallographic slip in Tin+1AlCn MAX phases

• DOI: 10.1016/j.scriptamat.2020.113698
• 发表时间: 2021-03
• 期刊: Scripta Materialia
• 影响因子: 6
• 作者: Zhiqiang Zhan;M. Radovic;Ankit Srivastava

Role of length-scale in machine learning based image analysis of ductile fracture surfaces

长度尺度在基于机器学习的延性断裂表面图像分析中的作用

• DOI: 10.1016/j.mechmat.2023.104661
• 发表时间: 2023
• 期刊: Mechanics of Materials
• 影响因子: 3.9
• 作者: Zheng, Xinzhu;Battalgazy, Bekassyl;Molkeri, Abhilash;Tsopanidis, Stylianos;Osovski, Shmuel;Srivastava, Ankit
• 通讯作者: Srivastava, Ankit