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.

该教师早期职业发展（CAREER）资助将重点量化微观结构变形机制对具有纳米层晶体结构的材料（例如锌、云母和某些碳化物）机械响应的影响。这些材料对于在极端环境（例如高温）下需要可靠性能的技术具有巨大的前景。然而，它们在关键应用中的使用受到严重限制，因为它们表现出极其依赖方向（各向异性）的行为，不能适应任意的形状变化，并且本质上是脆性的。另一方面，这些材料的各向异性使它们能够通过晶体滑移、裂纹和/或较小尺度的不稳定性来经历宏观变形，这反过来又可以显着提高它们的损伤容限和延展性。该研究项目将提供对纳米层晶体材料基于微结构的机械响应的基本理解，为微结构工程利用其损伤容限和延展性的应用铺平了可能性。这一目标将通过综合实验计算方法来实现，这将产生预测建模框架和多个长度尺度的实验数据。研究活动将辅之以一系列完全综合的教育和推广活动。该教育活动将通过开发交互式教学材料和新课程来加强本科和研究生水平的工程教育。外展活动将通过分别让德克萨斯州高中教师参与研究和学生参加夏令营来提高工程意识。这项研究的目标是双重的。首先，通过新颖的小规模原位实验，了解极端各向异性纳米层材料、氧化物、碳化物和氮化物中晶体滑移、裂纹和不稳定性的协同效应。其次，开发并验证基于晶体塑性的本构模型，该模型结合了非施密德效应、解理裂纹和局部不稳定性，以预测这些材料的微观结构敏感机械响应。这将为以下关键基本问题提供答案：（i）哪些材料特性或特性组合会影响单晶中滑移、裂纹和不稳定性的发生和传播？ (ii) 滑移、开裂和失稳对整体塑性变形和损伤容限的协同效应是什么？ (iii) 非施密德效应对裂纹和不稳定性的发生有何作用？ (iv) 晶间裂纹如何影响这些材料的多晶的损伤容限？该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。

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

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

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