Collaborative Research: Deformation Mechanisms in Microstructurally Tailored High Strength Alloys Near the Ideal Limit

合作研究：接近理想极限的微观结构定制高强度合金的变形机制

• 批准号: 2310306
• 负责人: Jason Trelewicz
• 金额: $ 42万
• 依托单位: SUNY at Stony Brook
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2310306&HistoricalAwards=false
• 关键词: Collaborative; Research; Deformation; Mechanisms; Microstructurally

NON-TECHNICAL DESCRIPTION: Materials with higher and higher strengths are often the target of materials scientists for structural engineering applications – stronger materials enable safer structures as well as lightweighting for more energy-efficient transportation. Several pathways are available for enhancing strength through control over defects in the material. However, efforts to-date have failed to bring material strengths anywhere near the holy grail of strengthening, referred to as the ideal strength. This failure has not come from a lack of materials engineering, nor would innovations in materials design or processing immediately solve the problem. Instead, prior approaches have been too limited in scope from the viewpoint of the material’s deformation physics, which is addressed in this research by considering novel design pathways for controlling material structure and, in turn, the defects that govern strength. The findings of this project are applicable to advanced materials with increased chemical complexity, which are desired for modern engineering applications. An interactive online learning module transcending traditional institutional barriers – denoted the Mechanics Interactive Teaming (MINT) initiative in engineering education – is being developed to engage students cooperatively at the partnering universities with new virtual learning modules focused on cutting-edge topics in materials science. The initial focus on graduate curricula is being broadened to reach undergraduates through the Women in Science and Engineering Program at Stony Brook University and further expanded for working professionals using relevant design problems through collaboration with the Advanced Casting Research Center at UC Irvine.TECHNICAL DESCRIPTION: This research enables materials with near-ideal strength by developing a fundamental understanding of dislocation nucleation and propagation as rate-limiting deformation mechanisms in nanostructured alloys where defect confinement and interaction with grain boundary and lattice solutes act as local barriers to plasticity. Specific research questions to be answered include: (i) what are the important transition states and associated energy barriers for dislocation nucleation at solute-decorated interfaces and for propagation within a nanoscale alloy crystal, (ii) how does interfacial structure and energy variation upon doping alter dislocation nucleation/propagation, and (iii) how do solute atoms inside the grain, which can potentially act as local pinning points but also alter the properties of the lattice, influence dislocation propagation? A practical hypothesis of this research is that the strength of nanocrystalline alloys can be maximized by synergistic doping to stabilize the grain boundaries against local plasticity and delay defect nucleation while simultaneously inhibiting dislocation propagation through the nanograin interiors. Using a combination of atomistic modeling, multi-modal structural characterization, and unique micromechanical testing, this hypothesis is being tested in nanostructured aluminum and copper alloys, where their intrinsically different stacking fault energies will provide access to different confined slip events. In a broad sense, this research will define new strengthening paradigms in nanoengineered metallic materials and establish the mechanistic underpinnings of solute-biased interfacial energy landscapes for understanding fundamental dislocation physics in confined slip environments.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.

非技术描述：具有越来越高强度的材料通常是材料科学家用于结构工程应用的目标-更强的材料可以实现更安全的结构以及更节能的运输轻量化。有几种途径可用于通过控制材料中的缺陷来提高强度。 然而，迄今为止的努力未能使材料强度接近强化的圣杯，即理想强度。这种失败并不是因为缺乏材料工程，材料设计或加工方面的创新也不会立即解决问题。相反，从材料变形物理学的角度来看，现有方法的范围过于有限，本研究通过考虑控制材料结构的新设计途径以及控制强度的缺陷来解决这一问题。该项目的研究结果适用于化学复杂性增加的先进材料，这是现代工程应用所需的。正在开发一个超越传统制度障碍的互动式在线学习模块-表示工程教育中的力学互动团队（MINT）倡议-旨在通过新的虚拟学习模块与合作大学的学生合作，重点关注材料科学的前沿主题。通过斯托尼布鲁克大学的女性科学与工程项目，最初对研究生课程的关注正在扩大到本科生，并通过与加州大学欧文分校先进铸造研究中心的合作，进一步扩大到使用相关设计问题的工作专业人员。技术描述：这项研究通过对位错成核和传播的基本理解，使材料具有接近理想的强度，纳米结构合金中的限制变形机制，其中缺陷限制以及与晶界和晶格溶质的相互作用作为塑性的局部障碍。需要回答的具体研究问题包括：（i）对于溶质修饰界面处的位错成核和纳米级合金晶体内的传播，什么是重要的过渡态和相关的能垒，（ii）掺杂时的界面结构和能量变化如何改变位错成核/传播，以及（iii）晶粒内的溶质原子如何，其可以潜在地作为局部钉扎点，但也改变晶格的性质，影响位错传播？本研究的一个实际假设是，纳米晶合金的强度可以通过协同掺杂来最大化，以稳定晶界，防止局部塑性和延迟缺陷成核，同时抑制位错通过纳米晶粒内部的传播。使用原子建模，多模态结构表征和独特的微机械测试的组合，这一假设正在测试中的纳米结构的铝和铜合金，其本质上不同的堆垛层错能将提供访问不同的限制滑移事件。从广义上讲，这项研究将定义新的纳米工程金属材料的强化范例，并建立溶质偏置界面能景观的机械基础，以了解基本的位错物理学在限制滑移environments.This奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。